GIS Mapping Workshop

Join the IU digital humanities landscape by converting your data into digital maps.

Pouyan Shahidi

IU scholars from history to area studies, diaspora studies, art history, geography, history of science and more benefit from visualizing and analyzing data on maps in their research, teaching, and publications. Any piece of data that is associated with a location on the Earth can be visualized and analyzed using Global Information Systems (GIS) software. The end results, comprises a variety of digital assets including but not limited to digital maps, geospatial databases, charts, and web apps that can be published in, or linked to books, articles, and websites, or as independent databases to be used by other scholars. It is even possible to create “storymaps” on platforms that allow you unfold your narrative while taking your reader on a tour of visualized data on maps and using multimedia. Like in the case of other digital humanities methods, learning how to work with software and platforms is much easier that what the fancy outcome of them might suggest in the first glance.

In this two-part asynchronous workshop, we intend to, first, give IU faculty and students an overview of what GIS can do for them through highlighting a few works by their peers; and second, to quickly direct them to easy-to-follow workflows that breakdown the process of build a digital mapping project into simple steps. These workflows, which can be used in your research projects or for your in-classroom pedagogical needs, covers a variety of ArcGIS desktop and online platforms. The contents of the workshop are a mixture of brief texts, screen shots and short screen recordings, as well as links to external sources for diving deeper into narrower technical matters. This asynchronous workshop will be gradually updated to cover more GIS skills that might be useful in humanities, arts, and social sciences.

1 GIS for research in humanities

1.1      What is GIS mapping and how can it help research in humanities?

More or less like layers of different types of visualized data that you see every day on your phone’s map apps to, for example, find a burger place in the vicinity of your office, or the situation of traffic on your way home, time and place related historical data can be visualized and analyzed on a map. In this short introduction, you can see how a map of the whereabouts and the scholarly works of Avicenna (10-11 c. CE philosopher and physician), along with some other data from his time can help historical analysis. Watch 6:11 to 9:19 of our Digital Methods Workshop. You can also access the Slide deck of our workshop.

With this brief introduction in mind, let us see GIS method in action through a few ongoing humanities research projects at IU:

1.2 DATA COLLECTION AND DATA MANAGEMENT

In GIS mapping we deal with various types of data. On a typical map, for instance, you might see points representing entities such as cities, towns, or gas stations, lines representing highways and streets connecting these points, and polygons representing boundaries of a county or state, etc. Sometimes we even need to put a digitized map, a satellite or aerial photograph in its corresponding place on a map. The first type of geographic data that is used in mapping is called vector data, which contains latitude and longitude coordinates.  The second type, raster data, is constituted of a matrix of pixels (like those that make up your computer screen) where each cell contains information such as color values. You can think of rasters as, essentially, images like you would pull up on your computer. GIS software will automatically  plot vector data to the corresponding locations on the map. Raster data, on the other hand, must be manually placed on the map by the user through a process called “georeferencing”. You can explore the map collection of IU and familiarize yourself with how and where to find GIS and spatial data.

Data collection is usually the longest part of mapping projects. It is important to think in advance about the types of data that you might need in your project and to come up with a taxonomy for your data. Each category of data in your taxonomy will translate to a layer of features on your map.

1.2.1     General data management

In any digital humanities project, many files of various types and use are involved, and so, data management has a key role in insuring a smooth progress free of confusion and frustration. This is even more important in mapping projects, since the number of files generated by a GIS software can multiply exponentially. Watch this short video, from one of IDAH class visits, for an overview of how to manage your data.

Keep in mind that GIS software in the process of your project creates multitudes of files. While you do not need to directly work with those files, it is important to have separate folders for each dataset to avoid confusion. So do not hesitate to create a folder hierarchy with as many folders as needed.

1.2.2     Collecting and managing point data

One common type of data in GIS is point data—i.e., data that represents a distinct point on the map such as a point that represents the location of a city, a building, etc. Point data is arranged in spreadsheets and saved as CSV (comma-separated values) files before it can be visualized on map in a GIS software. Each data point is a row of the spreadsheet. The first column is usually a “geographic identifier” (GEOID) assigned by the user. This is a code to identify the point. The other columns of each data point contain a name, and various sorts of “attributes”. To make the location of a point known to the software each point needs either a latitude, longitude or, street address. (In historical research, these coordinates are often approximate due to a lack of precise geographic information.) The spreadsheet in the following example contains a list of medieval cities in the Khurasan region that fell along the journey of the famous 10-11 century philosopher, Avicenna (Ibn Sīnā). Each city has a latitude and longitude to locate it on the map. The next column shows which of these cities are mentioned in Avicenna’s autobiography and which ones are not. This way after mapping the points they can be visually distinguished from one another based on the latter attribute. If like this example, you have special characters, make sure to save your spreadsheet as “CSV UTF-8”.

1.2.3     Collaborative data entry

Digital humanities projects are often done through collaborations. In a classroom setting also learning is often more efficient when students work in teams. This short video from one of the IDAH class visits, provides a simple way collaborating in data collection.

1.2.4     Collecting and managing raster data (images)

The most common raster data used in digital humanities are digitized paper maps published in atlases, books, or articles. While you can always digitize the maps that you need, there are also plenty of online resources. The best way of finding maps, aerial photos, etc. is to get in touch with Map and Spatial data librarians. You can also explore IU map and GIS resources.

As we mentioned above, raster data is usually georeferenced on maps. The georeferencing process creates a group of files in the folder where your original image is located. To avoid confusion, it is wise to keep each image in a separate folder. Below is an example of two digitized paper maps from two historical atlases georeferenced in ArcGIS.

2 ArcGIS Platforms: ArcGIS Pro

Now that we have a general idea of GIS and its application to humanities, let us learn how to create maps using ArcGIS Pro 3.1 to which you have access through IU.

2.1      Installing ArcGIS Pro and logging in

First, use this link to download the installer from IU Ware and install the software. the Install the software on your machine. Running on your machine, you’ll see the following screen. On the lower right corner click on “Sign in Using Browser”.

This will open your internet browser and take you to the following page. In the filed under “Your ArcGIS organization’s URL type: IU. Then click on “Continue”. If you are not already logged into IU, you will be taken to IU Loggin page. Use your IU credentials to log in.

Once your are logged in, you will see the following message. Click on “Open ArcGIS Pro”.

2.2      Starting a new project

Watch these two short videos to learn how to start a new map project, and how to choose a base map.

2.3      Geospatial visualization (static and temporally dynamic) with ArcGIS Pro

2.3.1     Creating feature classes

Behind any map in ArcGIS is a “file geodatabase” that encompasses all the data that you add to your map. One way of keeping organized the data that you add to your map, is to categorize your data in subsets of this database called “feature class”. If you imagine a file geodatabase as a dresser, each feature class is like a drawer that you keep a similar type of data, e.g., points, lines, or polygons. Different types of data (e.g., points and lines) cannot be categorized under one feature class. Each feature class becomes a layer on your map.

This is why we emphasized (see above) that it is important to think about a taxonomy for the features that will appear on your map before and during data collection.

In the following video we learn how to create different feature classes for an example project. Our example project is to create a map that shows 1) The locations of a few cities in the medieval region of Khurasan; 2) A major trade road that connected them; 3) The borders of the Samanid kingdom (9-10 century CE) that ruled this region and beyond. I would like to put each type of feature under a separate feature class/map layer.

Now we are ready to add data to each feature class / layer.

2.3.2     Creating point data on a map

Learn how to add point data from a csv file to a map as a feature class / layer; how to label the points; how to style them; and how to make them visually distinct based on an attribute.

2.3.3     Georeferencing raster data on a map

Imagine you have a historical map of a region with some information on it such as the trade roads of a given period. How do you import such visual data from a paper map to your own map? The first step in doing this is to put a digitized image of the historical map on its corresponding place on your map. This process is called georeferencing. The following video teaches you how to do that.

One last point, if you make a mistake while georeferencing, you can always go to “Imagery” tab > “Georeference” tab and click on “Control Point Table”. Each row in this table represents a control point. You can turn control points on or off by clicking on the checkbox next to them. When turned off, a control point will be set aside from the process of georeferencing. You can also select a control points row on the table and, delete the wrong control point in the later table and permanently delete it by clicking on the icon shown below. Afterwards, you need to save your changes to this table as we saw in the video.

2.3.4     Creating and putting linear and polygonal data on a map

Now it is time to draw on the roads and borderlines of our georeferenced maps. The following videos show how to draw lines and polygons on appropriate layers / feature classes.

2.3.5     Converting time data (temporal data) to an animated map

Sometimes we need to work with data that changes with time. Historical urban development in a city, and the whereabouts of a traveler that is physically moving in time and location are two examples of such data. Watch this video to learn how to show changes or movements in time and location on a timelapse animated map.

3 ArcGIS Platforms: ArcGIS Insights

ArcGIS Insights is an online software for running geospatial analyses. This user-friendly platform helps the users of different skill levels conduct analysis such as aggregating data points that intersect or are contained by certain features on the map. The results can be depicted on integrated maps and charts of various types. Below, we will see a simple example of such analysis for our simple historical datasets. 

3.1      Running a geospatial analysis in ArcGIS Insights

In the following video we learn how to analyze the distribution of our data points across different features like boundaries of certain areas. We also learn how to depict that on interconnected maps and charts and share the results as an online workbook. 

In ArcGIS Insights you can also filter your point data based on a spatial relationship with a feature or a layer of features. For instance, in our sample data, you can filter the cities and roads that intersect with or fall under the borders of Ziyārīds. The resulting filtered data is automatically put under new data layers and can be readily converted to new maps. The GIS technical term for this process is “clipping data”. The following video shows how to perform data clipping in ArcGIS Insights.