A 1580 Map Shows Why Data Visualization Is Never Neutral

Nearly 450 years ago, an unnamed Ñudzahui painter mapped his community’s history and land claims for a Spanish king — on his own terms.The “Mapa de Teozacoalco” produced by the Relaciones geográficas survey (1580). Courtesy of the Joaquín García Icazbalceta Manuscript Collection, Benson Latin American Collection, LLILAS Benson Latin American Studies and Collections, The University of Texas at Austin. View a high-resolution version here. Listen to this article 0:00 Even from the highest point in town — the bell tower of the church of San Pedro Teozacoalco — it was impossible to see farther than a few kilometers in any direction. The two major mountain ranges that run along each of Mexico’s coasts converge in the region — what is today the Mexican state of Oaxaca — resulting in a “geological jumble” of tree-covered peaks and scrub-filled valleys, punctuated only by the occasional vertiginous cliff.The year was 1580, according to the Spanish. But the Ñudzahui (Mixtec) people had been navigating this terrain for millennia. The ridgelines that separated the main town of Teozacoalco from its 13 smaller dependencies were as familiar to the Ñudzahui as the backs of their hands. Even the growing number of Spanish colonial officials and other citizens of the Crown settling in the area had at least a general sense of the lay of the land. While this terrain could be learned through experience, there was still no way to see it all at once — not by those who climbed to the top of the bell tower, and certainly not by those like King Philip II of Spain, who would never set foot on the North American continent during his lifetime. Which was why the king — or, more accurately, his royal cosmographer, Juan López de Velasco — had requested a map.López de Velasco was hoping the king would benefit from something most people today take for granted: that by visualizing the region’s complex terrain, he would gain immediate insight into the land over which he sought to rule. The map he requested would take more than a year to research and design, and another three years to travel across the Atlantic. Now, nearly 450 years after its creation, the “Mapa de Teozacoalco,” as it has come to be called, exemplifies the central argument of “Data by Design”: that visualization is a tremendous form of power. This is true both because of the knowledge that visualization helps to surface, and because of the people who decide how to put that knowledge to use.In today’s world, we experience the power of visualization in ways large and small. It’s what pulls us into colorful charts of election returns, which show us quickly and clearly which candidate has prevailed. It’s what fills us with despair — or alternately, determination — when we see a graph of global temperatures rising. It’s what tells us to evacuate from the path of a hurricane when we see our town or city inside a shaded danger zone; or simply to move to another room of the house when we see our cell coverage has shrunk to a single bar.This power is real, and it is remarkably effective. But the appeal of visualization is inseparable from its danger. Because maps and charts (and their interactive analogues) all promise ease and efficiency, they mask their own complexity. And as data visualization has become a primary means by which we gain insight about the world, we have come to see these images simply as the way things are, rather than what they actually represent, which is a set of specific design decisions made by specific people, in specific places and times, and for specific purposes. Put another way: We too often assume that visualization is transparent, a method that lets us see through to the significance of the data underneath. But the reality is that the choices made when visualizing data are nearly as significant as the data itself.Which brings us back to the “Mapa de Teozacoalco.” The creator of this particular map was an Indigenous painter whose name was surely known to his family and friends, although it went unrecorded on the map itself. As a result, the Ñudzahui man’s name has been lost to time.We know from a 1583 inventory that the royal cosmographer, Juan López de Velasco, personally received the map, evidently one of dozens enclosed in a folder of “maps and plans” returned from the land he called New Spain. While there is no equivalent record that can attest to whether the king himself ever saw the map, let alone what insight he might have gained, we do know a great deal about his worldview: shaped by a literal Renaissance education; focused on questions of land and resources; and fixated on financial gain.This gives us some sense of the parts of the map that likely struck his eye. Perhaps the bold brown footpaths that indicate the region’s major roads? Or the vinelike turquoise lines that reflect its many rivers? (Lest they be confused as mere embellishment, note that they are populated every so often by a scaly white fish.) The king would also likely have noted the numerous mountain ranges, and the churchlike icons that represent each of the towns in the larger community, or yuhuiayu. These icons were plotted so precisely in relation to the map’s natural features that they have been used by present-day archaeologists to pinpoint the locations of these historical towns.But would the king have known how to interpret the map’s circular projection, intended to signify the yuhuiayu‘s unity and wholeness, largely unfamiliar to European viewers, but typical of Mesoamerican mapping techniques of the time? And what of the bell tower of San Pedro Teozacoalco, depicted inside the circle on the upper left, atop which our own story began? Examining the map from a continent away, would the king have seen how this icon was intended to indicate the elevated status of the town of Teozacoalco, both as a colonial center and an enduring site of Native rule? Or would this very symbol of vision and power have remained, ironically, opaque to the Spanish king, its significance as obscured as the horizon to those who climbed the actual bell tower’s steps?Complete objectivity is an illusion; context and power always enter in.In truth, we cannot know precisely how the king might have interpreted the map. But with some knowledge of Ñudzahui history and culture, we can intuit at least a little about what the mapmaker wanted him to see. Consider the pairs of figures that rise up from the main town, plotted just to the right of the bell tower icon. These pairs represent the ruling lineage of the yuhuiayu. The bottom, we know from extensive scholarship on the subject, is the start of the third dynasty of Teozacoalco. The dynasties continue upward through six generations to the unmarried male heir, pictured alone at the top of the line, who was likely the Native ruler of Teozacoalco at the time.The ruling lineage of Teozacoalco, with the third dynasty of Teozacoalco on the bottom and the current ruler at the top.Scholars of Ñudzahui history have verified the accuracy of this genealogical diagram, as they have the longer family lines that appear on the left side of the page. But they have also documented something more: The information encoded in these diagrams mattered, and so did the manner in which the figures were drawn. As historian Yanna Yannakakis explains, the vertical genealogical structure that would have been legible to the Spanish king was not how the Ñudzahui people themselves understood their own history. In a culture in which marriages across ruling families were employed to forge political alliances and to build collective strength, the Ñudzahui conceived of the relationships among the ruling families of the region more as a network than as the simpler parallel lines depicted on the map. By drawing these lineages as visibly distinct from each other, even as their genealogies were known to be deeply intertwined, the mapmaker was very deliberately representing the history of his people in a visual language that the king of Spain — his intended viewer — could easily understand.The genealogies of Teozacoalco (center-left) and Tilantongo (far left) intentionally configured in two vertical lines.This is just one example of what can be gained by placing a map or chart in the specific context of its creation. It also shows the power that data visualization commands. This power derives both from the practice of visualization and from the people who put that practice to use. The Ñudzahui mapmaker was not merely employing his knowledge of European representational strategies to make the map easier for the king to interpret, after all.For the mapmaker, the king’s interpretation carried profound personal and political stakes. By 1580, when he put his final flourishes on the map, his people had already endured several generations of colonial rule. King Philip II’s ascent to the throne, in 1556, had ushered in a proliferation of new laws increasing Spanish control over the Native population, and Spanish profit from Native land. More recently, the effects of colonization had become visceral, with a deadly epidemic that raged across the region for several years. This environment would have confirmed the urgency of the mapmaker’s charge. It was not merely to respond to a royal decree; it was to create an unequivocal attestation to his people’s sovereignty and their enduring claims to the land.Here visualization, power, and context come together, illustrating how the intrinsic capabilities of data visualization are inflected by specific design decisions — decisions that are, in turn, influenced by the worlds in which those decisions were made. It can be tempting to believe that it is possible to employ data visualization in a neutral capacity, just as it can be tempting to believe in the complete objectivity of the information on display. But complete objectivity is an illusion; context and power always enter in. This argument does not undermine the value or function of data visualization. On the