How to Select Polygons which contain Points in ArcMap

January 17th, 2008

Occasionally I write about things on this site that I haven’t been easily able to discover via a Google search – here’s one of them – I’ve been doing some GIS work for a client recently and I found myself befuddled by a simple problem.

When we’re faced with a situation where we have a large number of xy or lat long points in arcmap (for instance, when we’ve got a lot of yield monitor data) overlaid over the top of a polygon data set (for instance, block or paddock boundary shapefiles) in arcGis, what’s the best way to select only those paddocks (polygon shapefiles) which contain logged points?

Actually, it’s not too difficult. You have to use something called an ‘intersect’.

Select By Location in ArcGIS

Basically, in ArcGIS / ArcMap lingo, you’re selecting a feature (our block boundary polygons) that intercept or contain elements from another feature (our point data layer) – as shown below, with the selected features highlighted in cyan.

To achieve this type of select, you need to go to the select menu, and choose ‘select by location’ – which will take you to the ‘select by location’ dialogue – (you can click the thumbnail to view full size).

In the dialogue, first you need to select the data layer that contains the polygons / blocks / features you’d like to select (select features FROM the following layer) and from there you need to chose ‘intersect’ in the drop-down followed by your points layer in the ‘features from this layer’ box.

After some processing, this will select all blocks / polygons / features that contain your points of interest.

Exporting a Selection to a new Shapefile in ArcGIS

Of course, now you’ll probably wish to export the selected features to a new layer – that process is described here – ‘Creating Subset Datasets in ArcGIS’

Entry Filed under: 4. Off-topic