Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

I've run in to a little problem. I have two sets of polygons with important attributes. I need to join over the attributes from the first set to the other, but I can't seem to figure out how. Theoretically it seems like an SQL right join, I think. Can you help?

The only way I can get this to work, I think, is the somehow copy the blue polygon. The first problem is that not all of the red polygons are completely inside the blue, but I have selected by centroid (I need to do this). The second problem is that there could be 1, 2, 3 or more red polygons per blue.

The example below would be Blue1+Red1 and Blue1+Red2 and so on.

I have ArcEditor 10.1, QGis and FME.

I need to join the attributes from the red polygons over to the blue polygon.

share|improve this question
add comment

3 Answers

up vote 4 down vote accepted

in arcgis you want to do a spatial join.
from the arctoolbox select analysis tools, overlay, spatial join.
spatial join
choose the one to many operation.

"ESRI desktop help 10.1"
use the intersect match option.
In my example the first time I got the target features switched so pay attention to the target and join features.

share|improve this answer
    
This worked. Thanks!! –  Teresa Jan 15 '13 at 8:59
add comment

It sounds like you need to do a Many-To-One join instead of the typical One-To-Many join. This is possible with ArcGIS and FME.

In ArcGIS simply perform the spatial join as usual, but uncheck the "Keep All Target Features" option. This will create an output with a copy of each target feature for each joined join feature. If you need to have the attributes from each join feature on the same target feature you can simply perform attribute joins.

FME can do the same thing with the SpatialRelator. Just choose to load all related into a list and use the ListExploder.

share|improve this answer
add comment

I would use the Union tool of ArcGIS for Desktop to do this. How it works is described here.

share|improve this answer
    
I can't use the Union-tool, as I will get null-values where there is no overlap. I need the geography of the blue polygons with the attributes plus the red attributes. –  Teresa Jan 14 '13 at 22:43
    
Have you looked at Intersect instead? It's just like Union but only keeps areas of overlap. –  PolyGeo Jan 14 '13 at 23:23
    
+1 Union would be my first choice. @Teresa have you experimented with the parameters of the union tool? Otherwise, try other options in the overlay toolset. –  Aaron Jan 14 '13 at 23:24
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.