Evaluating student progress hinges on data quality. Are the roads connected? Are the polygons closed? Are features tagged with correct attribution? Overpass Turbo is a web-based, interactive tool that let’s you interrogate the data and assess its geometric and referential quality. Although the Overpass Turbo interface is relatively simple, it is a fairly robust tool, rich in features. There are some sample queries provided as examples, a helpful wizard to help get you create your own queries, and the ability to export data. To use it, you zoom to the area of interest, presumably where your student has digitized some data, use the wizard to query for ‘park’, or ‘building’ or ‘path’.

The example below shows the text of the query on the left-hand half and the query output on the right. This instance shows a query for ‘building’. The data that satisfy that criterion are highlighted in the output pane. OverpassTurbo example

A particularly useful function of Overpass Turbo is found under the ‘Export’ tab. You have the ability to export data, maps, and your queries. The data export includes several well-supported formats so you can make the data available for other downstream projects, such as advanced cartography or spatial analysis. Options to export the map image include an interactive map, useful for providing direct feedback to mappers.

More information can be found on the Overpass Turbo page on the OpenStreetMap wiki.

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