Merge layers without losing excess observations in ArcGIS?

Question

I am currently using Arcgis to map UK Election Data. I merged a shapefile and a datatset together and have starting looking at trends. See image below.

Then I looked at the attribute table of the merged item and realised I'd done something very stupid; My dataset had 20,000 observations, whereas my district map of the UK contained just over 400 items, since it's based on local authority level. In looking at the attribute table I realised that 400 records have been merged and the rest of the observations seemingly not there.

Thinking about it now, of course this would happen. I suppose what I wanted instead is a density or average of all the records relating to a particular polygon. For example, every observation contains a 1 - 10 score on a question around how succesfull the government has been. Obviously I don't want tp map just one observation per area, but instead want to aggregate ALL OBSERVATIONS per area.

Therefore my question is how to accomplish this in ArcGis, and how to merge layers without deleting all the 'excess' observations unneeded by the shapefile?

Answer 1

Use the spatial join tool to get the attributes from your polygons into your observations. Then summarize whatever attributes you need an join back to the polygon data.

Alternatively, use the spatial join tool to either SUM, MEAN, COUNT, FIRST, LAST... attributes. You set this by setting the join operation to 'JOIN_ONE_TO_MANY', then in the field mapping section, right click and select the merge rule: Numeric Field

Text Field

This way you can summarize whatever attributes from the observations you need and they will be added to the polygon attributes in the output file of the spatial join.

Answer 2

As my comment has noted, you may use Spatial Join tool to spatial join the observation layer to the district layer and summarize your variable field by using the stat options within the field mapping merge rule.