Category Archives: Tool

Tool: XML

XML stands for EXtensible Markup Language. It is a language like HTML that allows you to markup your data. You can use XML to markup a letter, documents or other forms of data. One of the most prominent XML editors is called oXygen, which has XML development tools for people with all different skill levels. XML, however, does not have predefined tags. This means that the user decides what the tags are and how the document is going to be structured.

One benefit of XML is that it conveys less tangible information that accompanies data. For example, with a letter, XML enables you to tag areas of the letter that were damaged or areas that had notes in the margins. By using XML, you preserve the information found in physical documents. You can tag your text based on content and/or structure. If you did not use XML and simply accepted the text as data from a machine, you would lose the context of the document.

Data is stored in plain text format in XML. This makes it easier to share data, preserve data, and understand data. The standard markup format in XML is <tag> TEXT </tag>.

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Original Joshua Chamberlain letter (left) that was then decoded and transcribed in an oXygen file (right). Credit: Ana Timoney-Gomez (created for Introduction to Digital and Computational Studies, Fall 2015).

 

Tool: GIS

ArcGIS is a software program that scholars and researchers in many disciplines use to produce and analyze geospatial data. GIS stands for geographic information system. Spatial analysis is a way to gather information on the locations and features of spatial data. Digital humanists can use spatial analysis to help answer questions about location and visualization.

ArcGIS offers many tools in order to examine spatial data.

Georeferencing puts data into a spatial context. This means that an image can be assigned real-world coordinates. For example, one project georeferenced old maps. Before georeferencing, these maps existed without spatial context or a coordinate system. These old maps were then referenced to modern maps using control points that were found on both maps. Referencing using control points enabled the old maps to become digital representations of a physical space. Georeferencing can also indicate the accuracy of older images.

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ArcGIS Map of Present Day Topo Map and Historical Map of Gettysburg layered on top. Credit: Ana Timoney-Gomez (created for Introduction to Digital and Computational Studies, Fall 2015).

The georeferenced version of the map was adjusted according to control points from a modern topo map. The distortion of the georeferenced map shows that the original map did not have the same spatial context or coordinate system as the modern map. Georeferencing encourages us to look at the details and distinct features found on maps.

Geoprocessing is a tool that enables you to manipulate spatial data, which means that your input data will look different from your output data. Geoprocessing focuses on the features of the input image, such as visibility and terrain.

ArcGIS (and ArcScene) can now also perform 3-D image modelling.

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ArcGIS 3-D image model. The pink color shows what Joshua Chamberlain was able to see at Gettysburg. Credit: Ana Timoney-Gomez (created for Introduction to Digital and Computational Studies, Fall 2015).

 

Although GIS is an helpful tool if you are working with environmental data, it is also extremely useful in many other areas (mapping, census data, business, health, migration, etc.). ArcGIS now also offers a collaborative web version that allows you to share content and project layers.

Further Reading: The Spatial Humanities: GIS and the Future of Humanities Scholarship edited by David J. Bodenhamer, John Corrigan, Trevor M. Harris.

 

Digital and Computational Toolbox: Gephi

Gephi is an interactive visualization platform. It forms network connections based on the relationship of data inputs. Gephi is open-source, which means that anyone can access it and users can also help improve the Gephi’s design and functionality. Gephi can generate data visualizations for different kinds of networks, graphs, and complex systems. Gephi enables you to create visual representations of data that could uncover hidden network connections. Users can then understand the intricacies and underlying trends in graphs. The two basic elements of Gephi visualizations are nodes (essentially a data point) and edges (connection between two or more nodes).

Gephi is already being used in DCS classes and projects at Bowdoin. This fall, students in Introduction to Digital and Computational Studies (INTD 1100) used Gephi to visualize Joshua Chamberlain’s correspondence network. The visualizations below represent Chamberlain’s overall correspondence during the Civil War. Students visited Bowdoin’s Special Collections and Archives to see the original Chamberlain letters and then created data visualizations in Gephi.

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Further Reading: Visualizations and Historical Arguments by John Theibault.