Querying OpenStreetMap tags by polygon using QGIS?

Question

If I understand OpenStreetMap (OSM) correctly, all objects essentially have associated tags based on type of object (street, building etc) ...

Can I use QGIS to obtain the statistics of different commonly used tags in that area so that I can have an idea of the feature distribution?

Answer 1

Do you want to do something like "count the number of buildings in area x"?

You can do that in QGIS

1. Load the OSM file using Openstreetmap plugin.
2. Check the attribute table now.
3. A query such as tags LIKE '%"building"%' should select only those features which have the building tag

To get statistics per area, I'd suggest the following approach:

1. Select buildings like described above
2. export the features to Shapefile using "Save as ..." from layer context menu
3. Replace building polygons by centroids
4. Use "Points in polygon" tool to count points per area

If you are selecting the area manually using e.g. freehand selection tool:

1. Select all features within your region
2. Use "Search only selected" option in attribute table and
3. Use above mentioned query