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The ArcGIS documentation for the Data Access Search Cursor states:

The records returned by SearchCursor can be constrained to match attribute criteria or spatial criteria.

But I can't see any example of how to specify spatial criteria when calling the search cursor. For this example I have a geometry and wish to constrain the results of the search cursor to only features which both intersect that geometry and meet other attribute criteria. e.g.

with arcpy.da.SearchCursor(fc,field_list,
                          "Admin_Code is null and shape intersects admin_area_geometry") 

I understand that I could perform a search cursor with the attribute query and then use the geometry intersects method but this would be slow to have to loop through each feature.

How can I specify both the spatial criteria when creating a search cursor?

  • Can you expand more what you mean by "intersect that geometry". Are you wanting to intersect two layers or one layer with itself? – artwork21 Jul 25 '15 at 11:59
  • It's two layers - I want to base an ID/admin_code on the intersecting polygon, but only need to identify those intersecting the input admin area where the admin_code is null - hence my reluctance to loop through all features. – kes Jul 25 '15 at 12:13
  • 2
    I wonder if the documentation is simply alluding to using SelectLayerByLocation before arcpy.da.SearchCursor. – PolyGeo Jul 25 '15 at 12:56
  • Thanks @PolyGeo, that worked - I used select by location to give a combination of spatial + attribute condition. Hadn't realised the cursors now accept feature layers which I spotted in another of your answers. – kes Jul 25 '15 at 15:43
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I would suggest using a where clause to lessen the impact of pulling out geometry info that way you are not iterating through the entire table:

import arcpy

fc = 'c:/base/data.gdb/roads'
class_field = 'Road Class'
name_field = 'Name'

# Create an expression with proper delimiters
expression = arcpy.AddFieldDelimiters(fc, name_field) + ' = 2'

# Create a search cursor using an SQL expression
with arcpy.da.SearchCursor(fc, [class_field, name_field, SHAPE@],
                           where_clause=expression) as cursor:
    for row in cursor:
        # continue with logic
  • Thanks - that's where I'm at but I'd also like to limit the search cursor with a spatial condition, as hinted at in the ESRI docs.. frustratingly this would be easy in SQL with ST_INTERSECTS but I'm finding it difficult to replicate in ArcPy.. – kes Jul 25 '15 at 12:15

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