I have polygon data on coral reefs at great barrier reef and separate point data for areas of coral bleaching. I have created a clip that only includes points that exist with in the reef polygons. However I need to be able to identify polygons that have bleaching points in them from those that do not. So for example I would like to be able to click on a polygon that has a bleaching point in it and it automatically select all the other polygons that do?
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2 Answers
you can use a select by location (from the selection menu) to identify all polygons that contain your bleaching data points. then add a field (options/add field...) to the reef polygon attribute table, and calculate values for the selected features with the field calculator (right click on the field name, select 'field calculator')to assign a value to differentiate between bleached and unbleached reefs (Y/N or 1/0).
If you want to select all polygons with a bleaching point in them, you can "select > select by location".
If you want to select all polgon with a given characterstic when you click on it, you need to use "dissolve" in order to have multipart poylgon. The first step would be a "spatial join" in order to find out which polygons include a point .
