Amélia Polónia, Historian, Associated Professor of the University of Porto (This email address is being protected from spambots. You need JavaScript enabled to view it. )

Amândio Barros, Historian, PhD, (This email address is being protected from spambots. You need JavaScript enabled to view it. )

Miguel Nogueira, Geographer, University of Porto (This email address is being protected from spambots. You need JavaScript enabled to view it. )

Abstract: On a globalised world, the geography of contacts, interactions and exchanges is based, each time more, upon an isotropic world, where distance (or proximity) and accessibility don’t seem to compromise the contacts and relations between human beings; new technologies play an unprecedented role in the territorial expression of network connections. Our aim is to address the question in what extent did territory conditioned contacts and networks in the First Global Age. Under DynCoopNet Project, the study of cooperation and trade networks wants to bring up scientific debate meant to clarify that question. Mapping historical data about commercial networks, assuming an intrinsic spatial component, implies spatial visualization in order to comprehend the nature of such networks, their design, extension and intensity. However, when dealing with fuzzy and geographically non-systematic data, researcher’s interpretations and data classification might misinform geotagging. Practical examples will be given and visualised, based on DynCoopNet (ESF- TECT/EUROCORES research project), as well as other works of the Portuguese research team.

Key-words: historical data visualization; First Global Age; trade networks; thematic cartography; mapping time-space connections.

About the authors: Amélia Polónia, Associated Professor at the University of Porto. Researcher of CITCEM (Transdisciplinary Research Centre: Culture/ Space/ Memory). Principal Investigator of the Portuguese team of DynCoopNet (Dynamic Complexity of Cooperation-Based Self-Organizing Commercial Networks in the First Global Age). CRP of EUROCORES (European Collaborative Research Programme) - ESF (European Science Foundation). Main domains of research: Trade Networks in the Early Modern Age; Portuguese Overseas Expansion; Social History of Maritime Communities; Seaports History.

Amândio Barros, Historian, PhD, Pos-Doc student; Member of the Portuguese team of DynCoopNet (Dynamic Complexity of Cooperation-Based Self-Organizing Commercial Networks in the First Global Age). CRP of EUROCORES (European Collaborative Research Programme) - ESF (European Science Foundation). Researcher of CITCEM (Transdisciplinary Research Centre: Culture/ Space/ Memory) Main interests: Seaports Studies, Economic, Social, and Maritime History.

Miguel Nogueira, MSc, Cartographer at the University of Porto. Consultant on development and execution of thematic cartography projects. Member of the Portuguese team of DynCoopNet (Dynamic Complexity of Cooperation-Based Self-Organizing Commercial Networks in the First Global Age). CRP of EUROCORES (European Collaborative Research Programme) - ESF (European Science Foundation). Main interests: thematic cartography, graphic communication and data visualization.

1. Introduction

This paper is a joint initiative of a geographer/cartographer and two historians, members of the research project DynCoopNet (acronym for "Dynamic Complexity of Cooperation-Based Self-Organizing Commercial Networks in the First Global Age") approved by the European Science Foundation’s programme EUROCORES (European Collaborative Research), as a project of the scheme program TECT (The Evolution of Cooperation and Trading).

It aims to deal with some practical problems that arise from the multidisciplinary specificity of this project in which visualization of historical data assumes an important role. We’ll attempt to centre this paper on the discussion of crucial problems that arise from:

a. The transference of the historical sources semantics of the (qualitative data) to the objectivity of geotagged references;

b. The implications resulting from the spatial models available to visualize and represent historical and spatial dynamics in networks (spatialization vs. mapping);

c. The implications of reciprocal transferences between agent attributes and space attributes.

As the paper seeks to disseminate some questions arising from the abovementioned DynCoopNet project, we'll summarise its main assumptions, according to the DynCoopNet project description guide-lines (2006).

This multi-national and multi-disciplinary collaborative research project (CRP) – DynCoopNet - addresses the EUROCORES Scheme program TECT through the exam of cooperation patterns among merchants and between merchants and other social groups, with particular focus on commercial networks framed on the global domains of Iberian monarchies, 1400-1800.

As primary theoretical assumptions, the project assumes that a) the world economy of the First Global Age (1400-1800) was a dynamic, open, complex, non-linear system; b) diversity among geographic locations constitutes an aspect of the system's complexity, which requires that data be georeferenced in order to analyze geographic contexts and understand connections among places; c) in this first global world, the history of any place can't be understood without examining how it was connected to other locations and to the system as a whole; and d) cooperation between agents remotely located bind them together, which can be expressed by the existence of self-organized commercial networks..

Through a convergence of methods unusual in the historical social sciences, the CRP intends to reveal the mechanisms of cooperation that permitted merchants and other social agents to establish and sustain often long-distance networks. After defining the characteristics and roles of cooperation that were established in the early days of the First Global Age, the CRP will identify and analyze the emergence of new forms of commercial relationships in order to understand the system's transformation to a world economy in which agent-based cooperation is assumed as an essential means to sustain network connections between locations.

The strategy and work plan of the DynCoopNet collaborative research community are guided by three goals: a) assess and document the nature of cooperative behaviour that shaped the self-organizing commercial networks linking various locations during the first global age; b) assess and map the evolution of cooperation in self-organizing commercial networks over various temporal scales at local, regional and global geographical levels; and c) reconstitute these networks and dynamics through mathematical resources and mathematical modelling able to fulfil gaps and reconstitute models that the empirical work of historians reveals unable to accomplish.

To reach these goals, DynCoopNet will make use of data gathering specifically directed toward understanding the evolution of cooperation and the structure and dynamics of commercial networks of the First Global Age. Data gathering will result from the exploratory work on different (in nature and typology) data sources of the sixteenth and seventeenth centuries. Most of it is qualitative data, expressed on complex and frequently unclear semantics. As far as the Portuguese team concerns, we’ll try to address the theoretical framework of the project through an empirical work centred on Simon Ruiz, a new Christian merchant, which commercial and financial company archive is kept at the Valladolid Provincial Archive1. Hopefully we’ll benefit from the existence of extended serial data gathered on sources of two kinds: bills of exchange and merchant correspondence. The team seeks to promote a systematic data gathering able to answer multidisciplinary demands and methodologies, such as GIS and mathematical modelling. To achieve this goal, DynCoopNet Portuguese team will create a database, oriented by the social networks theories and assumptions. It will be based on TimeLink software2, which architecture follows an agent based data registration, centred on individuals, aiming to gather elements related to their identification, their location (in time and space), their personal attributes (including their status in familial, professional, political, economics, religious and cultural spheres), their economic functions, as well as social, familial and political ones, and significantly, their connections. Data for each individual and for each link established between individuals will be assembled. However, systematic data and structured historical information about individuals' relationships it's very difficult to get; and that explains part of the major problems we'll have to resolve.

The central research targets of the analytical framework will be as follows: a) reconstitution of networks; b) appraisal of network models: networks topology, connectivity and density; c) identification of variables which interfere in the model; d) identification of cooperative behaviours and their connection with the enterprise objectives; e) space -time representation of cooperation networks ant its evolution in time; and f) appraisal of the spatial nodules and spatial connections of the networks, essaying to identify some main attributes of space and its influential projections on the networks under study and vice-versa.(DynCoopNet Portuguese team report October 2008)3.

Since the very beginning, the team proposed itself to use GIS technology and methodologies to structure, manage, analyze, and model geospatial, temporal, and historical components of cooperative trading information, in the assumption that GIS technology would enable georeferencing information based on associated locations, as well as the visualization of diachronic evolutions of networks and cooperative behaviours. We’re based on the assumption that GIS offers a data integration engine and visualization tool to bring together layers of information necessary to understand the high levels of cooperation and the transformation of the world economic system throughout the First Global Age (Owens 2007; Yuan 2008). At the conceptual and computational levels, GIS methodologies seemed to offer ontological and semantic approaches to define entities of interest and discern their cooperative relationships. However, checking its adequacy to our aims and data we concluded that the current GIS technology has only limited capabilities to handle with temporal. In fact, GIS is capable of explore, define and precise geotagged space references, but is not so proficient with fuzzy and diffused references, and hardly with space-time intersections. Or shall we ask what GIS expects from historians and historical data? This famine data consuming tool, capable of digest huge amounts of information and revolve it in such ways that human expertise wouldn’t be so capable to do, expects precision and consistency, specially when it comes to spatial data. Therefore, we proceeded looking for new approaches.

The workshop held in Madrid, in September 2008 was a major event in what concerns this purpose. The discussion overtaken was based on different perspectives presented by geographic information scientists, historical geographers, cartographers, geomatics engineers, and computer scientists. The presentations4 and the panel discussion of the workshop, coordinated by Monica Wachowicz, were structured “… on the basis of the three “spaces” paradigm proposed by Ernst Cassirer (1874-1945), a philosopher of the Marburg school, who described a learning process as a truly dynamic activity within the mind of the human experience of spaces and time. The spaces may assume different forms, from an observed space through sensors and senses (perceptual space), to an abstract model of space (symbolic space), to a higher level of concepts incorporated in an abstract internal space (cognitive space)” (Madrid Workshop Report 2008)5. The workshop also aimed to summarise, present and discuss the theory, methodologies and tools able to be applied to the strategy and work plan of the DynCoopNet Project. Through the development of geo-computational models (such as agent-based modelling or the fuzzy rule-based modelling), the dynamic and complex mechanisms of cooperative trading should also be revealed (Cf. Owens, Coppola, Szidarovsky 2008). For now, we won’t focus on this approach.

In fact, the CRP proposes to make heavy use of geo-visualization methods in the form of statistics, animation, and visual analytics to explore spatial and temporal distributions and relationships among trading groups and trading locations. Spatial analysis techniques will be used to assess the similarity of the social and economic settings of locations. Based on the similarity assessment, these techniques will be employed to investigate how geographic relationships among locations are related to the institutional, economic and cultural environments of these places and how those relationships promoted or hampered cooperative trading. Models of dynamic social networks will be evaluated for their appropriateness in modelling trade cooperation and in examining the mechanisms by which cooperative relationships were established and maintained (DynCoopNet project description guide-lines 2006).

Geotagged representations emerge, thus, as a main intention of our project. However, some problems seem to arise compromising the full accomplishment of these goals.

2. Challenges to solve, problems to discuss

2.1. From semantics to geotagged visualisation

Many of the spatio-temporal data sets being generated today are from Earth Observation Systems, geo-positioning and tracking, mobile sensors, outcomes of models, and many other sources. Scientists are currently facing the challenges related to the great increase of data volume of spatio-temporal databases due to improvements in data acquisition, validation, archiving, and distribution (e.g. instruments, sensors, computational resources, information infrastructures, and volunteer geoinformation). In contrast, historical data sets are gathered in a sporadic manner, and the similarities, differences, inconsistencies and deductions among these data sets are not known.” (Madrid Workshop Report 2008., p. 5-6)

To stress the judgement stated in the previous quotation, a presentation of the historical sources we deal with is needed.

We are working with qualitative and written texts, produced in the sixteenth century. These very heterogeneous texts that we must recover, assemble, systematize and turn into databases’ fields and cells. Then, we must systematize the data by using statistical tools and visualize it by using spacio-temporal methodologies and tools. To give provide an idea of the data extension, we expect to collect about 10.000 bills of exchange and 12.000 commercial letters, which will be turned into cc. 50.000 digitalized images. The nature of the sources may be visualized by the in images 1,2,3.


Images 1, 2 and 3

Facing these contingencies of data gathering, the difficulty to overtake the obstacles imposed by the nature of the sources and the absence of standard data or rigorous layouts of the information are overwhelming, as the following examples prove. That’s why we seek for practical answers that enable us to build space-time representations that can be scientifically validated and explored.

The next examples will give us an idea of the obstacles we’re dealing with. Let’s focus on those that seem to be the simplest ones: geographical references given by the sources are heterogeneous, either mentioning very specific or general indications too vague to be correctly mapped. We may be dealing (most of the time we are), within the same documental corpora, with a roll of geographic references that will oscillate from Porto, Lisbon, Genoa, Barcelona to Galicia, Flanders, Brabant, Baltic ports or even Brazil or East Indias… It seems quite clearly a scale issue, not the scale of the map itself but the geographical disaggregation of the data. Ones may find references to seaports or cities, along with references to broader regions or even countries or continents! This inconsistency compromises the balance and equilibrium among the spatial references and expressions of the phenomena projected onto them. The combination of micro and macro references or, in other words, the use of different spatial units to accommodate geo data, if cartographically accepted, will demand a lot of creativity from the mapmaker and, even the, pass erroneous/misguided information to a inexperienced map-reader.

In fact, under the sphere of mapmaking and visualization, during the process of historical source exploration and systematization of geodata, the coexistence of precise and vague place mentions is a significant problem when it comes to provide researcher and/or map reader with a detailed, accurate but simultaneously broad depict a given phenomena. . In the case of mentions from members of a small Portuguese seaport deceased abroad, what shall we do with states like: "dead in the Atlantic coming back home", or "dead in Brazil", or "dead nearby saint Tome" (Polónia 2007, vol. II, p.333-334).

Besides the immediate problem of historical evolution of the toponymy, or even its extinction, not to mention the difficulties in reading sixteenth century handwriting’s documents, we must be also aware that under the scope of an international research project we intend to merge geographical databases collected by each team into a major catalogue. It means that risks of overlapped, unlinked or unrelated geo references must be minimized. The worldwide geographical databases, such as Geonames6, available on line and generally used to geotagging historical references don’t, in fact, respond satisfactorily to our time and space categorisation requirements. Should we allege the arrangement and conversion of historical identification of places? Should we convert them to the present covenanted classification? Keep the local designation? Use a universal one? The establishment of a world scale place codification able to assign to each place a primary key/code would prevent such confusions.

Plus, in a scenario where the heterogeneity of geographical references is solved, we face an additional difficulty: the place names’ territorial expression. The same toponymy may refer either to a specific place or to an administrative or even natural, but, definitely, broader circumscription. The geographic implications of such almost imperceptible nuance might also compromise the affectation of data to a geographical feature and, in consequence, compromise the architecture of the geodatabase and further map reading and analyses.

A brief and particular reflection on geographical circumscriptions as features will emphasise additional problems. Whenever the spatial unit is graphically expressed a point on a surface (e g. a seaport city, a commercial trade fair, etc.), the location might be assumed as prevailed in time…However, most commonly at a local scale and micro analyses, some places might have disappeared, changed their names or even changed their location (in the case of seaport villages, for some natural reason, they might have been displaced for safer positions).

Another question arises on circumscriptions graphically expressed as areas: shall we design and consider those we have nowadays and currently in use or those existed in the historical period we are dealing with (and so, drawn as they were shaped)? Authors always believed that the correct option will be the use of the one’s defined in the historical times they are studying, even if it demands an extra effort and additional (parallel) research on such reconstitution of space. But how to uniform those circumscriptions in a worldwide level, and in global spaces such as Iberian Peninsula, the Europe as a all or Brazil, India, Spanish Indies? The challenge is, again, overwhelming.

Summing up, decisions about the spatial level of data representation (local, Iberian, European, worldwide territories), the choice between the past or present territorial locations/extensions of geofeatures, or even the idiom that should be used to identify those features, will always have to be discussed and accorded between multiple and multidisciplinary teams.

The discussion will continue, now concerning the selective and cautious analysis and evaluation process that historical/spatial researchers usually have to go trough when exploring the sources they work with. An assessment is needed when a sample is all that was obtained, and that can be more or less representative of the data. That means that resulting data available after the critical reading and demanding validation process, being both historical and geographical, must be evaluated and integrated (or not). This process will also have implications on the mapping process; ones need to recognize if after such a scrupulous filtering and validation, the remaining data would have enough consistency to be mapped. If transferred into a map, will it be enough representative of the phenomena as a whole? When questioning and debating the scientific consistency and uniformity of the variables to map, indispensable for the validation of the data to represent, geotagging seems to be a lesser problem.

And what about the standardization of geographical representations based in such diverse sources that involve so heterogeneous geographical references, so diverse typology of historical data and so chronologically extended periods? The evolutionary character of data is very important, especially when considering 400 years of dynamic evolution on spatial patterns of the phenomena under study.

Remaining on the discussion of the implications of the transference process from the historical sources semantics to visualization: shall we assume the simplest representation of historical phenomena or, on the contrary, be receptive to the historical complexity of dynamics that makes each event almost unique? Simplicity or complexity on data representation? In some cases, simplification of the data collected would facilitate data analyses and consequent mapping. Finding the limits under which information might be dispensable could always be a practice in order to simplify visualisation but only if not compromising the geographical lectures of variables. Spatial filtering may obscure fine detail information that is often of interest (Tobler, 1987; Slocum, 1998).

Most of thematic maps portraying movement or flows are based on a two entrance table, where origin and destination clarify the demands of such displacements. So, cartographers solved their problems on visualizing the spatial transference of goods, capital, people, ideas, etc. with flow maps, and with a from-to relationship (Dent 1999). After years persuading historians to systematise their approach to their sources, actually we came to realize that, in some, or even in most of the cases, precious geographic references were conferred secondary importance or even lost when focusing their attention on explicit retrieval of geo facts. A geographically trained ability and sensitivity in reading an historical source assume determinant role on its exploration.

An interesting case for discussion could be found on Barros’s work (2007). In this exercise, this historian pretends to expose how a simple (simplistic) geographical two-entrance database (origin and destiny) would camouflage important and significant geographical lectures of phenomena. The map on image 4, “Vila Flor’s merchants and the costumes transportation from Segovia to Porto” is a explicit example of how a direct and non-reflected approach on historical sources might lead to imprecise registers of movements and, consequently, to misguided representation on map of those same movements upon space.


Image 4 

A merchant somewhere in Vila Flor (Portugal) is on business. Exploring his contacts network, he is capable of taking merchandise from Segovia (Spain) and placing it on the market in Porto (Porto). What might seem to be, in space – and map – an easy design has, actually, serious considerations. The first one: shall we place him in Vila Flor, where he is from, or in Segovia, the departing point of the merchant circuit? This displacement of geographical features will be more detailed discussed in point 2.3 of this paper. For now, other evidences arise from further depiction of the source. A apparently and tempting simple and straight connection between Segovia and Porto became, in fact, a journey trough Spanish markets: from Segovia the merchandise head to Northeast to Medina del Campo, then went trough Tordesilhas, Ourense and towards east, till reach the port city of Redondela, where the merchandise was shipped and sail to Porto by the Atlantic!!! The redesign of this map is amazing. Ones can never neglect the spatial readings, interpretations and contributes that this larger episode - and map – bring to local/region histories. The option for simplicity, and the absence of the most complex itinerary described on the source would exclude places that were, in fact, part of a trade route that could be, or not, a commonly repeated one (which has to be confirmed by historians).

Another example makes it clearer. Gathering data from notary registers of ship freights, the historian may use a two entrance table, where origin and destination clarify maritime displacement, giving origin to a map flow (Image 5). Or, in alternative, he can include all the stops and scales of the trip (Image 6) giving thus another projection of places that would be totally forgotten (invisible because not considered) on the previous mapping representation. The trips from Portugal to Brazil are a good example, since they were almost never direct ones. Mentioning only the departing and arrival points we would almost totally exclude the West coast of Africa, a territory that nourished slave trade. Brazilian trade routes were, in fact, not bidirectional ones, but triangular or even more complex ones, involving departing points in Portugal, a call in Madeira , Cape Vert or Canaries to board wine, another one in Africa, where wine was changed by slaves, a third one in Brazil, and a return to Portugal, with sugar, cotton and other colonial commodities. This typical itinerary could also include, during the period under study, a potential trip from Brazil to Spanish Indies, where more slaves were disembarked. To represent all this complexity would a flow map be the right one? Should the proposal of image 5 be appropriate? Or should a cartographic solution like the one adopted in image 6 be more adequate?


Images 5 and 6 

Regardless all this disquietedness, we are regularly constructing perceptual maps - those in which the space is produced and read (or vice versa) through sensors and senses of thirds parties, those we can criticise (in a strict scientific historical sense) and filtrate, but not substitute by a more rigorous representation; our maps will always reflect the focus of the producers of the sources, their aptitude or incapacity to the accuracy, to clear cut (or not) representations of the reality and the interpretation given by historians and cartographers.

Historical documental sources might contain and represent different images of the reality. The explorer of the data sets his aims and establishes and defines the details as well as the focus of the space and then produces different versions of the same reality. The visualization of an overseas journey, whether is described by a sailor, a merchant, a captain or a ship-scribe will have different written narrative and, consequently, different opportunities of exploration and interpretations. Sailors will describe it with all the details about departing ports, scales (commercial or logistics), times spent in ports of call, weather, wind, travel accidents, and so on… For the same travel, a merchant would describe it referring the departing and arrival point, with much more data on the business, products, prices, and analysing or referring to seaports, mentioning details totally disregarded by the sailor.

The data transfer from this approach, frequently merely sensorial, thus not controlled by the rational or by a technical regard, to a map, which can be a symbolic or a cognitive representation becomes, thus, a huge problem, for historians and for mapmakers. This discussion leds us to further reflection: as a mapmakers, we produce scientific and technically accurate maps or, on the contrary, we are just the materializing agents of pre-assumed mental conceptualizations of spatial (co)relations, or even the intermediaries of the sensorial, perceptual or even affective maps of our ancestors? Additionally, projecting abstract models of space, and then constructing a symbolic space, will amplify our problems. Essaying an higher level of conceptualization incorporated in an analytical map, or in a cartogram, which provide us a cognitive apprehension of the space, leave us facing even much more delicate and difficult challenges.

2.2. Between mapping and spatialization: the right choice to visualize historical dynamics

Creating effective flow maps trough a careful and thoughtful design plan represents one of the more difficult challenges for the map designer” (Borden Dent, 1999).

Flow maps, the privileged map solution to map movement between places, it’s a complex assignment (Dent, 1999).

Recovering the above debate on the difficulties on mapping different geographies what’s the most adequate solution to visualize trade networks? We know they depend essentially on movement (of commodities and trade agents) and on connections... is it fair to think that flow maps the more adequate map solution to visualize trade networks? At this point, it might be useful to introduce an unpretentious discussion on how to map such movements and advocate cartographic solutions for it.

Flow maps are the most common and generalized technique to illustrate spatial movement. But critics on flow maps are also frequent among cartographers and map readers. Some would say that computerized flow maps are actually not as effective as the hand-made ones… A consensual explanation would rely on computer assisted cartography: the dissemination amid researchers and academics of desktop mapping software able them to easily manage and map additional amounts of information. Those resources lead to more visually appealing but we would say also more frequently imperceptible images of spatial behaviour and patterns of variables under study. Nevertheless, it is still being the classic solution to portrait movements.

Waldo Tobler was the first to develop software for displaying migration flows (SLOCUM, 1999). Since then, numerous techniques have been developed and tested in order to overcome problems with flow maps visualization.

Visualizing network flow and topology is challenging, because displaying a large number of connections with lines often results in visual clutter8. If there is proximity among origin points and/or among destination points then the cartographic output will denounce the confluence or even overlaying, along the same axis, of different expressions or intensities of fluxes. Then, to isolate a specific interpretation of a two point’s connection would turn out to be almost impossible9. Flow maps demand a lot of control on map design because of their complex graphic structures10.

A geographically centred critic is the linear linkage automatically created by most mapping software packages, neglecting the circumstances of spatial reality. Two points in space became connected, different sizes and values might infer the intensities, and arrows can indicate the direction of the movements. But, taking the example of commodities transportation from Porto to Mombaim a straight line connection between these two seaports would cross the Mediterranean and the Middle East…. So, within an historical context, especially when some historical sources allow us to create an even more precise design on commercial sea routes and maritime corridors11, those flows represented should be projected upon these pre-known routes. The same should be said about terrestrial trails: they should embrace the representation. Some networks and flow representations portrait organization aspects of the activities although at the expenses of not showing actual geographical routes12 and other geographical features relevant on those contexts.

Besides flow maps, a different creative but also arguable cartographic solution may lead to the use of choropleth maps with shading or colours. Assenting with Tobler, these do not actually show movement. Instead they show a change of state, but not the actual moves13


In the present day, generalization is abusively conferred to flow maps, and some authors14 even classify them as cartograms. Dent (1999) would prefer to call flow maps linear cartograms, to distinguish these from value-by-area cartograms. Most of them rip-off geographical aspects, namely location, in the pursuit of a clear image. Map generalizations, displacement of nodes, purging of non-significant data (already mention in this paper) are some of the artifices conducted.

In the pursuit of new solutions, spatialization model applied to network’s displays could be, as well, regarded as a possible answer15. Doantam Phan and other members from Stanford (PHAN et al., 2005) advocate satisfactory results on visualization of flows based on hierarchical clustering to create a flow tree that connects a source (the root) to a set of destinations (the leaves). By preserving branching substructure across flow maps with different roots that share a common set of nodes this Stanford group minimize edge crossings and distort node positions while maintain their relative position16.

The concept of spatialization17 that relies on dimension reduction techniques and layout algorithms to project relatedness in non-spatial data content lead to numerous experiences on displaying flows in networks. Distance-similarity metaphor Coined by Daniel Montello’s team (2003), using node-link displays e.g. multidimensional scaling plots, could, in fact, be an answer to visualize, in an abstract space, our networks of merchants. Based on nonmetric and non geographical references of proximity, using nodes as referential representations of individuals; using a network topology that avoid geotagged points, this model allow us to visualize hierarchical, radial, or even fuzzy networks,.. And even measure the relative “distance” and “similarity” between agents (our very own target), using physical direct metric distance across the network; network metric distance (physical separation between locations measured along the network links), and network topology (number of nods or area of the nodules represented). Such model solves some of our problems, although it wouldn’t fill our commitment with geographical space, since physical, financial, commercial or political geography is lost.


Other graphic solutions might bring interesting visualization of movements. Inventive cartographic design approach18 to depict events is claimed.

Nodes as units will prevent misguided interpretations about the spatial significance of a point and clear maps from those imperceptible, indiscernible jumble of lines that produce nothing but a conflictive and noisy image of movements. We have been testing and using symbol maps onto places portraying the qualitative or quantitative expressions of the phenomena combined with map design graphic artefacts to “embed map with movement/dynamic can produce readable spatial patterns19. Some lines (similarly designed) could be added to map to enforce main connections and directions. This would mean that network nodes could congregate and display data and graphic information of the role they play. Spatial interaction is guaranteed even with no jammed lines, even if the mapmaker might be in the need to create some illustrative graphic artefact to confer movement to data….

Spatialization might achieve interesting results when we’re trying to trace commercial contacts, to understand place hierarchies… At a cognitive level, map-reader will be even capable to construct a mental structured image of the phenomena mapped. It might even produce cognitively adequate and aesthetically pleasant display. But, giving privileges to the geometry of position, manipulating or even sacrificing the geographic location, readings of territory will be excluded. If we address the questions: where are those places, where are our merchants, why they are at a specific location… then, our compromise with space must be fulfilled. This question gets additional importance and relevance if ones considered the transference of attributes among space and merchants/agents. Base maps containing geographical information (such as road networks, natural features, etc.) are essential in order to enhance space reading and explain nodal connections. Furthermore, in a GIS georeferenced environment, operations such as overlaying different features (or even more complex GIS operations) will allow more significant retrieval results.

Geographical space has, in fact, attributes we don’t want to loose, under the risk of missing important if not determinant information. It could be essential to produce cognitive interpretations of the historical dynamics under study. Networks are established between individuals placed in different places. Their location is strategic in order to understand their business centrality or marginality, the access to maritime routes, to financial markets, to diplomatic, political, and influential centres.

Thus, we wish to map networks, not projecting them in an abstract space but in a concrete environment. Even if we consider that the use of geographical maps may be replaced by cartograms in a micro-spatial level of analysis, we can answer back that at a local and micro scale, distribution of agents in a small village, distribution of mechanic crafts by streets; distribution of violent practices by urban areas produces relevant historical analytical insights, able to clarify, to deepen or even to create cognitive understanding of the past.


Images 7 and 8 

GIS application to urban studies has the potential of building, according to Philip Abrams, the urban places as a social form in which “the essential properties of layer systems of social relations are grossly concentrated and intensified – to the point where residential size, density and heterogeneity, the formal characteristics of the town, appear to be in themselves constituent properties of at distinct social orders”20.

2.3. Implications of proximity and similarity principles on networks visualization

Despite all their celebrated potentialities, geographical maps may not fulfil the analytical and conceptual historical findings’ visualization requirements. Revisiting Tobler’s first geography law21 or even the cognitive version that inducted proximity/similarity principle22, new modelling experiences have come to light. Like the one presented by Montello (MONTELLO et al. in 2003) which states that closer things are more similar than distant things… We believe that this geographical conceptualization might not match our experience. Concrete examples may be given. If we take he case of New Christian merchant communities, we might find that important and decisive cultural, economical, religious similarities among merchants doing business in geographically distant locations are stronger, and create more permanent and structured networks than the effective proximity to other merchant or financial groups. In fact, when we look at the merchant sociological panorama in the First Global Age, we discover that being physically distant one from each other, doesn’t mean, in any moment that they are not closely tied by strong familial and business bonds. Within these communities, cultural and religious patterns are structural elements of closeness, despite the physical distance. If we wish to map such network connections we’ll probably produce a distorted visualization of geography. Centred on a cognitive representation of human agents’ proximity, ultimately we could find that Lima (Peru) is closer to Medina del Campo (Spain) than Medina to Barcelona (both in Spain). This said the cognitive representation of this reality would result in distorted maps. The similarity principle would affect the proximity principle at such a point that remoteness becomes closeness.

Visualization would have to express what we intend to be a new approach to space representation. We intend to project a sociological space, an economical setting, a religious framework. Does this mean that we should avoid mapping and prefer spatializations solutions? We don’t think so. Networks and connections between nodes need geographies in order to be understood. The existence of trade, financial markets and business hubs, and connecting these centres with the presence (or absence) of Inquisition courts and Inquisition representatives become central variables to be mapped. In this sense, maps are needed when one intends to understand geospatial patterns and relationships23, because we can’t separate relationships from the spatial attributes.

In the close relation established between individuals and geography (economic, social, financial, political, cultural, and religious) another topic of discussion emerges: the reciprocal transferences between agent attributes and space attributes.

2.4. Reciprocal transferences. Projections between agent attributes and space attributes

Moving on to another challenge, we would argue that mapping historical data doesn’t always reflects in fact, not even frequently, a real importance given to space. We usually map static frequencies of data, projected on some geotagged targets, without real concern about space and its interactions with individuals or historical dynamics. This is a major problem we have to deal with. Our database is framed by an agent based approach: we decided that our data gathering would have the economic/social agent as a base of our registers. According to this approach, space references are dependent on the agent register. In this sense, we are departing from the theoretical assumption that the agent frames the space with his action. But we easily catch the idea that the agent is a very mobile creature: he’s born at one place, marries in another, the head office of his business is in a different one, and he exercises his activities in different places and commercial hubs. How to deal with it? How to connect an individual to a territory in this so mobile world in which the main characteristic of the networks under study is precisely the dynamism, the complexity and self-organized schemes, most of the times unruled and undisciplined? How to project the action of men and the networks in which they are main agents? Centrality and eccentricity issues are core issues in this discussion. A merchant who has his company headquarters in Medina del Campo, but acts all over Europe, and takes Madrid as its main business centre must be georeferenced to Medina del Campo? A merchant which has representatives all over Europe should or shouldn’t be geotagged in relation to those places?

Let’s focus on the case of seaports studies. We state that the success of a seaport as an economic centre does not depend only on its status as a centre of overseas traffic or as a platform for incoming colonial merchandise. Ports only make sense when set firmly within the economic fabric of their country, region, and overseas connections. So, its complementarities with the domestic economy and, thus, with an extended hinterland, is also vital24 How to represent, in spatial terms, this connection, if the sources only gave us the references of the seaport and its revenues?

These theoretical insights lead us to another main question: is it possible that a seaport precinct looses protagonism overtime, without loosing centrality? This is the case of some Southern European seaports, especially those of the Italian maritime republics. As harbours, they had lost prominence and status. They lost traffic but did not lose a role as centres of economic growth because of the importance of their merchant communities in investment and trade activity in international networks. They were indeed one of the largest and most privileged foreign communities in Lisbon and Seville, acting as central traders in overseas ventures25. In fact, even though Italian seaports lost centrality in the Atlantic trade complex, their merchants, bankers and capital maintained a vital position in the world economy despite the marginalisation of their seaports.

Hamburg, on the contrary, was a hub of foreign agents, capitals and merchandise and an operational and logistic centre that provided men, ships, capital and a flag to those who, being at war, could not pursue traditional trade connections. The port of Hamburg was, simultaneously, an economic and financial centre, and its vitality and wealth depended over time on foreign capitals and economic agents, even if its domestic dynamics were also critical26. How to deal with this projections and retroprojections of seaports and trade agents?

What to do with the revenues of the Casa de Contratación de Seville that are managed by Italian merchants? Should they be affected to Seville and the Spanish crown or distribute, in our maps, by the Italian cities that are the headquarters of those business Companies? What to do with the Hamburg fleet freighted by Dutch, French, German or British subjects? Should they be summed up and graphically gathered in Hamburg, since all of them use its convenience flag, or otherwise be graphically attached to the hubs of residence of each of the merchants that freight the ships? Answering these questions will determine the cartographic results and its interpretations.

In fact, we are assuming that the activity of agents defines the dynamism of space, but won’t it be also otherwise? The profile of Seville as overseas hub or of Burgos has insurance centre or even Medina del Campo as financial centre and Madrid as political centre are influential in the attraction of merchant companies and foreign communities. The fact that Lima (Peru) becomes the Inquisition Court’s headquarters in Spanish America determined the defragmentation of New Christian community settled there. In what concerns natural features knowing that a point in a map is a seaport (navigable or sanded), accessed by river, located in a mountain or plain area, would be essential for the interpretation of the economic dynamics and level of activity of the networks settled therexxvi. The same way, existence of a bridge, being on a crossroad or in a local regional or overseas harbour becomes identically determinant. This means that the characteristics of the space can also be influential on the constitution, density and topology of merchants’ networks.

Understanding this reciprocal interaction between agents and space lead us to conceive space itself as an entity, and confer to it the same status as the individuals. Proceeding to the identification of space with a place name; location (with a geotagged reference), attributes (geographical, economic, social, religious …), and its functions (as a financial market; a faire; a seaport; an insurance centre; …) and connections, space will be taken as a central protagonist of our story. This understanding will enable us to cross agent activities with space features, and then discuss if and in which sense, intensity, and permeability the social agent and the space interact with each other… We are now far away of the simple and wise aim of visualizing trade and social networks on space… even if we didn’t gave up of it…This understanding will lead us to two major challenges: the first, related to the graphic semiology needed to expose and read the attributes of space; a second one, related to the potential of data retrieval. Based on this scheme, GIS tool could be maximized trough sql spatial equations and modelling able to (re)built historical knowledge of realities of First Global Age. From semantics of documental corpora to mathematical modelling, a long and difficult path has to be accomplished. Open debate will enable some problem solving…

3. Conclusion

As historical questions drive a significant part of the inquiry of DynCoopNet project, we are simultaneously conscious of the permeability between historical and geographical approaches as an essential methodology to follow. The bulk of evidence, or the evidence that provides the study’s key analytical framework, is structured and analyzed within one or more databases that record both location and time.

If geographical information provides a good share of the historical evidence, historical dynamics provides a good share of geographical evidence. And if geographical information systems are an indispensable tool to gather, structure and analyse geodata, the academic community evolved in spatial studies, specially the ones dealing with historical data, must be aware of implications and limitations of historical data, capable of castrate the most ambitious projects. Authors present key historical arguments in maps, particularly maps that visualize previously unknown or unexamined spatial relationships or patterns of change over time.

We strongly believe that diversity among geographic locations constitutes an aspect of the system's complexity, which requires a strong commitment to the geographical context and georeferenced data in order to analyze geographic contexts and understand connections among places

Space and time are key-elements of our work. More complex relations are established by the mutual and reciprocal connections between individuals, geographical and historical contexts. The three of them are entities of a system and their attributes define and are defined by each other. The cognitive apprehension of this interactions is based on complex models, some of them pre-established; others to be trial.

4. Acknowledgements

Author’s and the Portuguese team would like to address their acknowledgments to DynCoopNet project, and specially to Jack Owens, for his steady motivation, support and information’s flow on DynCoopNet issues, and to European Science Foundation’s programme EUROCORES (European Collaborative Research), as a project of the scheme program TECT (The Evolution of Cooperation and Trading). We also would like to thank Susana Pereira, Ana Sofia Ribeiro, master students of the Faculty of Arts of the University of Porto, and António Barros Cardoso, assistent professor of the Faculty of Arts of the University of Porto, whose data and maps were used in this paper. 

5. References

Barros, A., Mercadores e mercados têxteis na península Ibérica (séc. XVI) in “XVII Encontro da Associação Portuguesa de História Económica e Social - Globalização: Perspectivas de longo prazo”, Évora, 2007.

Dent, Borden D., Cartography: thematic map design, 5th ed., Boston: WCB/McGraw-Hill, 1999.

DynCoopNet Portuguese Team Report October 2008. Working paper. Internal circulation

DynCoopNet Project Description 2006. "Dynamic Complexity of Cooperation-Based Self-Organizing Commercial Networks in the First Global Age" project proposal addressed to the EUROCORES (European Collaborative Research) Scheme program, "The Evolution of Cooperation and Trading" (TECT). Information available at

FRABIKANT, Sara, MONTELLO, Daniel et al., The Distance-Similarity Metaphor in network display visualization in “Cartography and Geographic Information Science”, vol. 31, n.º 4, 2004, pp. 237-252.

KNOWLES, Anne Kelly, Emerging trends in Historical GIS, in "Emerging Trends in Historical GIS", special issue articles, Historical Geography, vol. 33, p. 7-13

KRAAK, Menno-Jan, ORMELING, Ferjan, Cartography: Visualisation of geospatial data, 2nd ed. Harlow: Pearson Education, 2003.

Madrid Workshop Report 2008: Scientific Report of ESF. Eurocores Workshop. Visualisation and Space-Time Representation of Dynamic, Non-Linear, Spatial Data in DynCoopNet and other TECT projects (Technical University of Madrid, 25-26 September 2008).

Owens, J., ‘What historians want from GIS’, ArcNews, Summer 2007. Available at ArcNews online -

Owens, J., Coppola, E., Szidarovsky, F., Fuzzy Rule-Based Modelling of Degrees of Trust in Cooperation-Based Networks: Close Research Collaboration among Domain Experts (Historians) and Mathematical Modellers, 2008. Available at

PHAN, Doantam et al., Flow Map Layout, Proceedings of the 2005 IEEE Symposium on Information Visualization, IEEE Computer Society , 2005.

Polónia, A, 2007, Expansão e Descobrimentos numa perspectiva local. O porto de Vila do Conde no século XVI, Imprensa Nacional-Casa da Moeda, Lisbon.

Slocum, Therry A. - Thematic cartography and visualization. Upper Saddle River: Prentice Hall, 1999.

Yuan,m 2008, ‘Dynamic GIS: recognising the dynamic nature of reality’, ArcNews, Spring 2008. Available at ArcNews online -

TOBLER, Waldo, Optimal Parsing of Large Arrays, s/d. Available at

1 Simon Ruiz was a merchant from Castille, whose expression as businessman went beyond Iberian frontiers, reaching all European trade circuits, as can be proved by his correspondence being extended all over Europe – Lisbon, Porto, Valencia, Genoa, Rouen, Rome, Venice, Lyon , and establishing a complex network of agents. Born in 1525/1526 in Belorado, Burgos, Spain, among an inexpressive wool merchant family, he began his career as a businessman with 25 years old, as a middleman of Ivon Rocaz, a Nante’s trader of cloth from Bretagne, who sent him some of his product to be sell in the Medina del Campo fair. The relevance of this market, considered as a neuralgic point of people, goods and credit , encouraged Simon Ruiz, who succeed through an intensive participation in business acting as a representative to other commercial partnerships, He seems to begin by placing individuals of his (aqui, sem dúvida, correcto) trust in key points of the network, as well as engaging a network of informants in important trade places, while trading textiles, but also olive oil, spices, indigo, salt or wheat. Simon Ruiz also invested in the trade with Spanish Indies (the West Indies), by establishing a trade company centred in Seville, but the severe income decrease in 1567 and 1568 made him focusing his investments mostly in France, Flanders and the ports of Bilbao, Alicante and Italy (DynCoopNetPortuguse teamreport, October 2008).

2 Time Link is a computer tool specially developed to support micro-historical research with a strong emphasis on network analysis and prosopography. The system is been developed at the University of Coimbra and has been used in different types of research. Recently it was used to create a database that congregates Parish records of a Portuguese town named Óbidos, from the 16th to the 18th centuries, containing more than 100.000 biographical references. Cf.

3 DynCoopNet team internal working paper. Not available.

4 Workshop Presentations available at

5 Scientific Report of ESF. Eurocores Workshop. Visualisation and Space-Time Representation of Dynamic, Non-Linear, Spatial Data in DynCoopNet and other TECT projects (Technical University of Madrid, 25-26 September 2008).


7 PHAN, Doantam et al., Flow Map Layout, Proceedings of the 2005 IEEE Symposium on Information Visualization, IEEE Computer Society , 2005.

8 even when cartographic design rules were respected

9 DENT, Borden D. - Cartography: thematic map design. 5th ed . Boston : WCB/McGraw-Hill, 1999, p. 221.

10 Some interesting results obtained under the scope of DynCoopNet researches are providing us with the paths of ships on some sectors of oceans.

11 DENT, Borden D. - Cartography: thematic map design, 5th ed., Boston: WCB/McGraw-Hill, 1999, p.233.

12 Tobler, Waldo, Mapping movement, 2003.

13 See RAISZ, Erwin, Principles of Cartography, New York, McGraw-Hill, 1962, pp. 218-220

14 FRABIKANT, Sara, MONTELLO, Daniel et al., The Distance-Similarity Metaphor in network display visualization in “Cartography and Geographic Information Science”, vol. 31, n.º 4, 2004, pp. 237-252.

15 PHAN, Doantam et al., Flow Map Layout, Proceedings of the 2005 IEEE Symposium on Information Visualization, IEEE Computer Society , 2005.

16 FABRIKANT et al., “The distance-similarity metaphor in network display spatializations” in Cartography and Geographic Information Science, vol. 31, n.º 4, 2004, pp. 237-252.

17 KRAAK, Menno-Jan, ORMELING, Ferjan, Cartography: Visualisation of geospatial data, 2nd ed. Harlow : Pearson Education, 2003.

18 Borden Dent exposed, supported and illustrated these innovative experiments (DENT, 1999, p. 231)

19 Philip Abrams – “Towns and economic growth: some theories and problems” in Philip Abrams and Edward A. Wrigley, Eds.- Towns in Societies: Essays in economic history and historical sociology, Cambridge, Cambridge University Press, 1978, p. 10.

20 "Everything is related to everything else, but near things are more related than distant things" in TOBLER, W. R. (1970). "A computer movie simulating urban growth in the Detroit region". Economic Geography, 46(2): 234-240.

21 FABRIKANT et al., “The distance-similarity metaphor in network display spatializations” in Cartography and Geographic Information Science, vol. 31, n.º 4, 2004, pp. 237-252.

22 KRAAK, Menno-Jan, ORMELING, Ferjan, Cartography: Visualisation of geospatial data, 2nd ed. Harlow : Pearson Education, 2003.

23 James Bird, “Seaport as a subset of gateways for regions. A research survey” in Progress in Human geography, 4 (1989), 360-370; James Bird, “Seaport development: some questions of scale” in Seaport systems and spatial change, ed. B. S. Hoyle and D. Hilling (London, 1984); James Bird, The Major Seaports of the U.K., (London, 1963), mostly chapter 1 – The development of Anyport; Gordon Jackson, “The Maritime Experience of a Region without Ports: Argyll, Scotland, c.1740-1840”, in International Journal of Maritime History, XVII, 2 (December 2005): 1-18.

24 Maria Valentina Cotta do Amaral, Privilégios de mercadores estrangeiros no reinado de D. João III, (Lisboa: Instituto de Alta Cultura, 1965).

25 Silvia Marzagalli, “Hamburg 1750-1850. L’adaptation d’une ville au changement de l’activité portuaire” in Les hommes et les pouvoirs dans la ville. XVIe-XXe. siècles, (Bordeaux, 2000), p. 89-115.

26 See KNOWLES, Anne Kelly, Emerging trends in Historical GIS, in "Emerging Trends in Historical GIS", special issue articles, Historical Geography, vol. 33, p. 7-13, and other articles by the same author.