Select mosaic datasets by Location in ArcGIS Pro

Summary

Mosaic Datasets are supported for use with the Select Layer by Location geoprocessing tool, but the workflow might not be intuitive, whether running the selection programmatically, or through the geoprocessing tool.

A mosaic dataset will be comprised of images, boundary layers, and footprints, which is what makes this workflow somewhat unique.

Note:
For the tool to run properly, we need to rely on the mosaic datasets footprint or boundary layer components - the image components are not valid inputs for the Select Layer by Location geoprocessing tool. 

Consider the example workflows below.

Running the Select Layer by Location tool on a mosaic dataset through the ArcGIS Pro GUI

1. Ensure we have a mosaic dataset created, and another feature layer (that overlaps our mosaic dataset) to use as our Selecting Features parameter. 
2. Open ArcGIS Pro, create a new project, and add our mosaic dataset and the overlapping layer to the new project. 
3. In the geoprocessing pane, search for and open the Select Layer by Location Data Management geoprocessing tool. 
4. Populate the tool, setting the mosaic dataset's footprint or boundary layer as the input, and our other overlapping layer as the Selecting Features, using a relationship of Intersect.
   • This selects the mosaic dataset's footprint, provided it intersects the selecting features layer appropriately. 
   • If using the mosaic dataset's image, the tool fails.

Running the Select by Location tool on a mosaic dataset using ArcPy

1. Ensure we have a mosaic dataset created, and another feature layer (that overlaps our mosaic dataset) to use as our Selecting Features. 
2. Open ArcGIS Pro, create a new project, and add our mosaic dataset and another overlapping layer to the new project. 
3. Consider the Python syntax for the Select Layer by Location geoprocessing tool: 

arcpy.management.SelectLayerByLocation(in_layer, {overlap_type}, {select_features}, {search_distance}, {selection_type}, {invert_spatial_relationship})

4. Adapt the script to rely on either the footprint or boundary layer as the input, with our other overlapping layer as the selecting features, using a relationship of intersect. 
   • Below is what the basic core script would look like, if we're relying on the intersect overlap type. 

arcpy.management.SelectLayerByLocation(MosaicDatasetName, "INTERSECT", SelectingLayerName)

5. To select the boundary or footprint used within our mosaic dataset using Python syntax, use the name of the mosaic dataset, followed by either  /Footprint or /Boundary, for example: MosaicDatasetName/Footprint or MosaicDatasetName/Boundary. 
6. A final version of the script looks something like the following:

arcpy.management.SelectLayerByLocation(MosaicDatasetName/Boundary, "INTERSECT", SelectingLayerName)

• This would select the boundary layer within a mosaic dataset named "MosaicDatasetName" that intersects another layer named "SelectingLayerName."

Procedure

• Mosaic Datasets can be used with the Select Layer by Location geoprocessing tool, but the input features must be the footprint or boundary layers within the mosaic dataset. This is simple to do using the ArcGIS Pro geoprocessing pane. 
• When attempting to use this functionality using ArcPy, we access the boundary and footprint components by entering the name of our mosaic dataset, followed by either /Boundary or /Footprint. For example, "MosaicDatasetName/Boundary" or "MosaicDatasetName/Footprint"