How to calculate path length of each point from the start using arcpy?

So, you have a point feature class. Every point has a unique attribute that represents the sequence (e.g., from 1 to 100).

You want to get a point with PointID = 1, find a distance to the point with PointID = 2, and write this distance value into the Distance field in the feature class (Distance field for feature PointID2 will contain the distance from PointID1 to PointID2).

This solution would work for Basic license.

import arcpy fc = r"C:\ArcGIS\Default.gdb\_PointDistanceFc" features = [f for f in arcpy.da.SearchCursor(fc,("PointID","SHAPE@"), sql_clause=(None,"ORDER BY PointID"))] index = 1 length = 0 update_values = [(0,0)] for f in features: if index < len(features): length += f[1].distanceTo(features[index][1]) index += 1 update_values.append((f[0],length)) else: pass with arcpy.da.UpdateCursor(fc,("Distance","PointID"),sql_clause=(None,"ORDER BY PointID")) as upd_cur: index = 0 for row in upd_cur: row[0] = update_values[index][1] upd_cur.updateRow(row) index += 1 

The UpdateCursor will write the length value to the field. It is important to order the point features in the sequence you want to calculate the length with (you cannot rely on the OID since those might not match the order of features creation). Here is the sample result: