Python script to find out if two layers are overlapping

[Anonymous User]

As part of QAQC, I have to routinely check if all vector line data is buffered on the buffered layer. The layers are: vector line layer, buffer layer, and grid number layer. As of right now, I scan the entire county boundary to see if there is any vector line data that is not buffered on the buffer layer. If it is not buffered, I need to find out which grid number the problem resides. 

I would like to make a python script that would check to see if all vector line data (layer 1) is overlaying the buffered layer (layer 2) and if not, which grid number (layer 3) is the problem. 

Does anyone have any experience trying to write a python script that can tell if one layer is spatially overlaying another layer?

Code examples would be much appreciated. 

[JoeBorgione]

I haven't done it specifically, but a spatial selection or a series of them ought to do the trick

[XanderBakker]

Hi ggroshans_GreenvilleWater ,

Can you provide a screenshot showing the lines, buffers and grids or provide a sample of your data? There are a couple of things that might complicate this and I would like to see some specific situations to see what would be possible.

[Anonymous User]

Hi Xander, 

Thank you for your help. I have attached three screenshots. 1) A view of the vector line data, the buffer layer, and an example of how the vector line data may not correspond to the buffer layer, 2) A screenshot of my table of contents, and 3) A zoomed out view to show the grid layer (e.g., screenshot 1 is within grid 38).

[AndrewLaws2]

What's the field name used in mapnum_copy for labelling?

[Anonymous User]

Thanks for all your help so far.  The field name used in mapnum_copy for labeling is called MapNum

[AndrewLaws2]

import arcpy

arcpy.MakeFeatureLayer_management('water_main_copy', 'water_main_copy_lyr')

arcpy.SelectLayerByLocation_management('water_main_copy_lyr', "WITHIN", 'water_main_buffer')

arcpy.SelectLayerByLocation_management('water_main_copy', "", "", "", "SWITCH_SELECTION")

arcpy.SelectLayerByLocation_management('mapnum_copy', "INTERSECT", 'water_main_copy')

fc = 'mapnum_copy'
field = 'MapNum'
cursor = arcpy.SearchCursor(fc)
for row in cursor:
    print(row.getValue(field))
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This would be a way to make a feature layer. Give it a try and if it gives you errors just follow the similar naming convention for feature layers for water_main_buffer and mapnum_copy.

The text that comes will be the Map Numbers with unbuffered water mains.

Hope this helps!

[AndrewLaws2]

Hi, I use a similar script from the Python window in ArcMap

##running from Python window in ArcMap with layers already MXD and using layer names as per your post

import arcpy

arcpy.SelectLayerByLocation_management('layer1', "WITHIN", 'layer2')

arcpy.SelectLayerByLocation_management('layer1', "", "", "", "SWITCH_SELECTION")

arcpy.SelectLayerByLocation_management('layer3', "INTERSECT", 'layer1')

fc = 'layer3'
field = 'layer3_field_that_contains_grid_name'
cursor = arcpy.SearchCursor(fc)
for row in cursor:
     print(row.getValue(field))

[AndrewLaws2]

What's the name of the labeling field in mapnum_copy?

[JoeBorgione]

Using the syntax highlighter makes code reading much easier:

##running from Python window in ArcMap with layers already MXD and using layer names as per your post

import arcpy

arcpy.SelectLayerByLocation_management('layer1', "WITHIN", 'layer2')

arcpy.SelectLayerByLocation_management('layer1', "", "", "", "SWITCH_SELECTION")

arcpy.SelectLayerByLocation_management('layer3', "INTERSECT", 'layer1')

fc = 'layer3'
field = 'layer3_field_that_contains_grid_name'
cursor = arcpy.SearchCursor(fc)
for row in cursor:‍‍‍‍‍‍‍‍‍‍‍‍‍‍