Spatial join: Joining all attributes to a polygon layer IF they correspond with the highest value of one of the attributes

[JessieFoest]

Dear ArcGIS community,

I am trying to add attribute information of a soil type polygon layer to a biodiversity (output) polygon layer, where both polygon layers are different (and thus, there are different soil types in each biodiversity polygon). I only want to include the soil type that is most common in the biodiversity polygons (i.e. largest area) Thus, I thought, I would preform a Union, then calculate the area of each section and put this largest area and the soil type of this area in centroids. Then I wanted to perform a Spatial join of these centroids to the original biodiversity layer, but in a way that ONLY the soil types would be added if that soil type is most common based on the area I calculated before.

I have, however not found a way to do this (i.e. make the output soil type attribute dependent on if the corresponding area is larger than the other soil type areas within the biodiversity polygon).

What would be a way to approach this?

Thank you so much in advance, it really means a lot!

[JessieFoest]

I think I did not confuse them? the overlapping referred to the original situation where I had two different polygon layers (e.g. the soil type polygons and the biodiversity polygons).

To clarify: Originally, I had a polygon (feature) layer for biodiversity (and the boundaries of this layer are to be the zones in the end-result), and a polygon layer for soil type. I converted the polygon layer for soil type into a raster, where each pixel contained information on the soil type number only (i.e. different classes?). Then, I used the Zonal statistics as table tool with as ' input feature zone data'  the biodiversity polygons, as 'zone field' a copy of the OBJECTID (to make it more stable), as 'Input value raster' the soil raster file, and as statistics type 'Majority'.

Thank you for taking the time to look into this question. I really appreciate it.

[DanPatterson_Retired]

intersection or combination might be the term I would use for two different layers.  Overlap often refers to just that within a layer, like when you buffers can 'overlap' in a layer.  semantics aside..

If you have two raster layers and you want to do 'stuff' with them you need to ensure that you are aware of the extent of both (left,right,top,bottom), their cell sizes, whether the edges of the cells align (snap raster issues), and their cell sizes.

Given the above, you could have taken two rasters, each representing a different parameter and each having a different set of classes.  In your case you have not one...but two rasters in integer form that represent some variable... soil class and biodiversity.  In a case like this you might want to look at the 'association' (don't use correlation as the term) between those two.  The tool to use in that case would be the Combine tool

Combine—Help | ArcGIS for Desktop

This will tell you the various combinations of the classes between the two variables.  In effect, does X in the Biodiversity layer tend to be more prevelant in areas where Soil Y occurs.  It does this by producing a raster that shows the unique combinations between the two inputs and their classes.  the cell counts relative to their total presence in the landscape gives you data akin to producing a contingency table in a Chi-squared analysis.  So, don't rule out this as an option...the zonal statistics stuff involving means, standard deviations only are useful when one of the rasters represent a variable measure on an interval/ratio scale ... like precipitation, temperature, income, age... relative to a raster  classified on a nominal basis ... like soil type, census tracts, townships etc... Why?  there is no such thing as a mean biodiversity, because biodiversity is at best an index and not a physical quantity.