Seeking tool to use in ArcPy that does opposite of Near?

Question

I have a shapefile with many (1000s) points grouped by attributes. I need to determine the distance between each point and the point furthest from it that shares the same group attribute.

Is there a tool that does the opposite of Near (proximity toolset) i.e. that would ideally operate like this Near By Group tool?

Answer 1

This is a sample I've written quickly to solve your problem. As an example, we will be working with US cities finding furthest cities within every state. As you have ArcGIS Desktop installed, you have the necessary data to run the code.

Note that there will be one row less in the output table because District Columbia has only one city. I've also left some comments to help you understand the workflow. The execution time for the code is something under 1 minute (3149 cities in the input feature class).

import os
import arcpy
from arcpy.da import SearchCursor

arcpy.env.overwriteOutput = True

cities = r'C:\Program Files (x86)\ArcGIS\Desktop10.4\TemplateData\TemplateData.gdb\USA\cities'
group_attr = 'STATE_NAME'
scratch_gdb = r'in_memory' #r'C:\GIS\Temp\ArcGISHomeFolder\empty.gdb'

grouping_vals = list(set(f[0] for f in SearchCursor(cities, group_attr))) #'OBJECTID < 20'
lookup = {}

for val in grouping_vals:
    print val
    #create a feature layer keeping only cities with a specific state
    feat_lyr_name = 'cities_lyr_' + val.replace(' ','')
    arcpy.MakeFeatureLayer_management(in_features=cities,
                                      out_layer=feat_lyr_name,
                                      where_clause=''' {0} = '{1}' '''.format(group_attr,val))

    #count number of cities in the state
    group_feature_count = int(arcpy.GetCount_management(in_rows=feat_lyr_name).getOutput(0))

    #generate near table for every city in the state (all-to-all)
    near_table = os.path.join(scratch_gdb,'near_{}'.format(val.replace(' ','')))
    arcpy.GenerateNearTable_analysis(in_features=feat_lyr_name, near_features=feat_lyr_name,
                                    out_table=near_table,
                                    closest='ALL')

    #compose a dictionary {source_fid: destination_fid} for only top rank (interested only in furthest)
    group_lookup = {f[0]:f[1] for f in SearchCursor(near_table, ['IN_FID','NEAR_FID','NEAR_RANK'],
                                                    where_clause='NEAR_RANK = {}'.format(group_feature_count-1),
                                                    sql_clause=(None, 'ORDER BY NEAR_RANK DESC'))}

    lookup.update(group_lookup)

#inserting new rows into a gdb table
with arcpy.da.InsertCursor(r'C:\GIS\Temp\ArcGISHomeFolder\Default.gdb\DistancesLookup',
                           ['SourceFID', 'DestinationFID']) as cur:
    for k, v in lookup.iteritems():
        cur.insertRow((k, v))

Answer 2

The workflow below is nearly identical to 1st answer, but uses no scripting:

# add coordinates to points to fascilitate distance calculations later on
arcpy.AddGeometryAttributes_management("points","POINT_X_Y_Z_M")

arcpy.SpatialJoin_analysis("points", "points","../points_SpatialJoin", "JOIN_ONE_TO_MANY", "INTERSECT", search_radius="1000000 Meters")
# select and delete non-matching pairs
arcpy.SelectLayerByAttribute_management("points_SpatialJoin", "CID <> CID_1")
arcpy.DeleteFeatures_management("points_SpatialJoin")
# add distance field and populate it
arcpy.AddField_management("points_SpatialJoin", "DISTANCE")
math.hypot( !POINT_X!- !POINT_X_1!, !POINT_Y!- !POINT_Y_1!)
# sort descending and delete identical 
arcpy.Sort_management("points_SpatialJoin", "../sorted", "DISTANCE DESCENDING")
arcpy.DeleteIdentical_management("sorted", fields="TARGET_FID")

Table of "sorted" has enough info to obtain this:

-1 BTW for ignoring wealth of available ArcGIS tools and asking for out of the box solution.