Hi,
I am busy spatially joining the attributes from a polygon layer (regional ecosystem information) to a point layer (scat survey sites). When I complete the spatial join (join features based on polygons which the points lie completely within) I find that the attributes from multiple polygons are joined to each of the points when the point only lies within one polygon (e.g. point 1 = vegtype1(wetland) AND vegtype2(non-remnant)). I suspect this may be due to the fact that the layers have different coordinate systems. I have attempted to project the layers in one coordinate system and reduce the XY tolerance however these changes don't seem to help. Does anyone have any suggestions.
Sunelle 😄
Hi Sunelle,
Assuming it isn't the result of differences in projections (and it is always wise to use the same projection when combining spatial data), there can be other reasons. Let's have a look at the help:
http://resources.arcgis.com/en/help/main/10.2/index.html#//00080000000q000000
I understand that the number of points in your output point feature class is higher than the number of points in your input featureclass. Is that correct?
If so, then I assume that during the spatial join your "join_operation" is set to "JOIN_ONE_TO_MANY". From the 10.2 Help:
If multiple join features are found that have the same spatial relationship with a single target feature, the output feature class will contain multiple copies (records) of the target feature. For example, if a single point target feature is found within two separate polygon join features, the output feature class will contain two copies of the target feature: one record with the attributes of one polygon, and another record with the attributes of the other polygon.
If you look at an input point that is found multiple times in your output and you perform an identify on your polygons, how many polygons are found at that location? If this is more than 1, your polygon feature class may contains regions (overlapping polygons).
Kind regards,
Xander
The number of points in my output point feature class in the same as my input point feature class (My join operation is set to JOIN_ONE_TO_ONE).
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I have checked the original attributes within the polygon layer as well to make sure that polygons only have one vegetation value assigned.