Daily Archives: July 3, 2012
This being the time for Independence Day in the USA, wouldn’t it be interesting to use GIS to investigate if place names having “Independence Day” origins have a spatial pattern? Ask your students what names come to mind when they think of Independence Day. I chose four—Liberty, Independence, Freedom, and America (I even have a niece named Liberty!).
I started ArcMap and added the world street base map from ArcGIS Online. I then loaded the most comprehensive American cities shapefile I could find, with 23,435 cities. I used Find tool to locate all cities with Liberty, Independence, Freedom, or America in any part of the name, saving them one at a time into individual layers. Liberty was the most popular with 29 place names, the largest of which was Liberty, Missouri. Independence came in second with 10 instances with Independence, Missouri, topping the list with 112,301 people. Was Missouri the site of most of these 4th-of-July names? The maps showed Missouri to have a few, but the names were scattered from the mid-Atlantic states to the Midwest, 4 Liberties in eastern Iowa, a few names in the deep south and far west; nothing in Alaska or Hawaii. Was this pattern what you expected?
This exercise shows how easy it is to perform tasks in ArcGIS. I used the Find tool, highlighted place names matching the criterion, and then used Select because it allowed me to find all instances of the place name, wherever the chosen place name appeared, in any field. Second, using Selection -> Create Layer from Selected Features provided a quick way of creating new layers without having to create layer files or exporting the selection to new shapefiles or feature classes. Third, one can easily use standard symbols in nonstandard ways; the ovals I chose came from the Businesses symbol set. Finally, this exercise shows the ease of using ArcGIS Online data as a base map.
What other place names could you use in similar ways to investigate patterns?
Originally published, Jul 2, 2009