Determining spatial sort order with ArcPy? [closed]

Question

How do I determine if a varying hypothetical set of lines (example in image) needs to be sorted by X (longitude) rather than Y (latitude) programmatically to ensure they are ordered from 1 to 14 as described by the arrow?

The example set of lines is only an example and can occur in an number of different orientations and permutations.

I will always know which line needs to be 1 for each set of lines, but the rest of the lines need to be ordered in proper sequence.

UPDATE_05_18_2017: To clarify this post a bit if anyone comes across it in the future.

The problem:

1. Lines can come into the program in any arrangement;
2. Due to digitizing when creating these lines the (OBJECTID, OID, FID whatever) will also get scrambled;
3. A method was needed to order these lines;
4. The Sort tool, an SQL "ORDER BY" statement with a da.UpdateCursor, etc. would sort the records, but since the lines can come in any orientation, to my knowledge there is no way to achieve an accurate sort.

My work-around was to educate the editors so that while editing they maintained some logical OID order. With an ordered OID field I could then query and loop though the data reliably as desired.

I thought to calculate average bearings, and sort on their basis since lines will follow a defined orientation, but the lines shown in the example are 118.9degrees which would lend them to be sorted by Y:

    if 45 <= avgGbearing <=135 or 225 <= avgGbearing <= 315:

using the .firstPoint(shown), .midPoint or .lastPoint coordinate would not sort the lines 1 to 14 appropriately:

The data is stored in a Microsoft (JET) Access personal geodatabase. I am using ArcGIS Desktop version 10.1 ArcInfo License.

Answer 1

If you want to sort the features by X coordinate, you can use the Sort tool either by python script as shown below or manually by adding a field, calculating and sorting. This should work if your data looks like your screenshot:

Code:

import arcpy

fc=r'C:\test.gdb\polylines'
outfc=r'C:\test.gdb\polylines_sortedByX'

#Add a field to store X coordinates of each polyline centroid
arcpy.AddField_management(in_table=fc, field_name='Xsort', field_type='DOUBLE')

#Populate the field with X coordinates
with arcpy.da.UpdateCursor(fc,['Xsort','SHAPE@X']) as cursor:
    for row in cursor:
        row[0]=row[1]
        cursor.updateRow(row)

#Sort by the calculated X coordinates and output a new feature class
arcpy.Sort_management(in_dataset=fc, out_dataset=outfc, sort_field='Xsort')