For now, let’s talk about how to get started making your map. Shapefile is more popular, but Google uses KML. Spacial data commonly comes in one of two file formats: shapefile (.shp) and Keyhole Markup Language (.kml).
The purple shape on my map is made up of 702 points, but you could use far more points to get a higher-res shape. The more points you use to approximate curves, the higher-resolution your shapes will be-just like how more pixels per square-inch result in higher-resolution photos. For this reason, the shapes we plot on maps are often referred to as “polygons”-figures with three or more straight sides. If you zoom-in really close on my map, you can see how this seemingly curvy shape is actually made up of straight lines between points.
Shapes on a map, like my purple blob representing the school district, are actually just a series of individual coordinates that Google Maps connects with straight lines, like a connect-the-dots picture. Then, I right-clicked on the red marker hovering over the hotel, and I selected “What’s here?” I searched Google Maps for the address of this hotel: 1200 Hampton St., Columbia, SC. We are currently at a latitude of 34, and longitude of -81.03. Points, lines and shapes that we render on a map come from “spacial data.” All spacial data boils down to a fundamental unit: a pair of numbers representing a single geographic coordinate. You don’t need any special computer skills, but it really helps to have a basic technical understanding of the underlying data. Making and sharing a map like this is easy and free-all you need is a free Google account. They can click on the individual dots and see the address and phone number of each school. Users can zoom in, zoom out, and drag to explore in any direction. It has a shape-the purple blob showing the borders of the district. It has points-green dots showing the location of each school within the district. This is an interactive map of the public school district in which we are currently located.
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