PRJ Not Created with DefineProjection_management

e125818_MyCity

We have a python script that imports AutoCAD DWG files to SDE feature classes. These DWG files are created by various 3rd parties and are transmitted to us for import. One of the steps in our import process is to create a PRJ file for the DWG. Mostly, this works fine but about 5% of the DWG's have a problem when trying to create the PRJ file. We use arcpy.DefineProjection_management to create the PRJ and it always runs but doesn't always create the PRJ. When it doesn't, no error is thrown. The code just silently keeps going without creating the PRJ. Does anyone know what might be the problem or have similar issues?

Python versions: 2.7 and 3.13.7
Arcpy versions: 10.9.1 and 3.6.4
SDE version: 10.9.1

def project(strFullWorkingFilePath, dblScaleFactor):

    try:


        # Scale Factor: it gets multiplied by the false northing and easting to move the drawing.

        # Use Decimal data type instead of float in spatial ref calculation.

        sfi = Decimal(dblScaleFactor)

        sf = Decimal(1.0)/Decimal(sfi)

        fe_4204 = Decimal(1968500.0) * Decimal(sf)

        fn_4204 = Decimal(13123333.33333333) * Decimal(sf)


        # Build the coordinate system string that will be stored in the CAD file's PRJ file.

        Coordinate_System = "PROJCS['NAD_1983_StatePlane_Texas_South_Central_FIPS_4204_Feet',GEOGCS['GCS_North_American_1983',DATUM['D_North_American_1983',SPHEROID['GRS_1980',6378137.0,298.257222101]],PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]],PROJECTION['Lambert_Conformal_Conic'],PARAMETER['False_Easting'," + str(fe_4204) + "],PARAMETER['False_Northing'," + str(fn_4204) + "],PARAMETER['Central_Meridian',-99.0],PARAMETER['Scale_Factor'," + str(sf) + "],PARAMETER['Standard_Parallel_1',28.38333333333333],PARAMETER['Standard_Parallel_2',30.28333333333333],PARAMETER['Latitude_Of_Origin',27.83333333333333],UNIT['Foot_US',0.3048006096012192]]"


        # Tool: Define Projection creates the correct PRJ file along side the CAD file.

        arcpy.DefineProjection_management(strFullWorkingFilePath, Coordinate_System)

Tonyalmeida

First make sure you are pointing to "D:\Working\Drawing.dwg\Polyline"

check to make sure the prj is being created with something like

import os
import arcpy

prj_path = os.path.splitext(strFullWorkingFilePath)[0] + ".prj"

arcpy.AddMessage("========================================")
arcpy.AddMessage("DWG: {}".format(strFullWorkingFilePath))
arcpy.AddMessage("DWG exists: {}".format(os.path.exists(strFullWorkingFilePath)))
arcpy.AddMessage("PRJ: {}".format(prj_path))
arcpy.AddMessage("PRJ exists BEFORE: {}".format(os.path.exists(prj_path)))

try:
    arcpy.DefineProjection_management(
        strFullWorkingFilePath,
        Coordinate_System
    )

    arcpy.AddMessage("DefineProjection returned successfully.")

except Exception as ex:
    arcpy.AddError("DefineProjection failed: {}".format(ex))
    arcpy.AddError(arcpy.GetMessages(2))
    raise

arcpy.AddMessage("PRJ exists AFTER: {}".format(os.path.exists(prj_path)))

if os.path.exists(prj_path):
    arcpy.AddMessage(
        "PRJ size: {} bytes".format(os.path.getsize(prj_path))
    )
else:
    arcpy.AddError(
        "DefineProjection returned successfully, but PRJ does not exist!"
    )

Define the projection with something like,

arcpy.DefineProjection_management(
    strFullWorkingFilePath,
    Coordinate_System
)

prj_path = os.path.splitext(strFullWorkingFilePath)[0] + ".prj"

if not os.path.exists(prj_path):
    arcpy.AddWarning(
        "DefineProjection completed but PRJ was not created: {}".format(prj_path)
    )
    raise RuntimeError(
        "PRJ file was not created: {}".format(prj_path)
    )

arcpy.AddMessage("PRJ created successfully: {}".format(prj_path))

For NAD 1983 StatePlane Texas South Central FIPS 4204 Feet, the common Esri WKID is 2278.

import arcpy
from decimal import Decimal

sfi = Decimal(str(dblScaleFactor))
sf = Decimal("1") / sfi

fe_4204 = Decimal("1968500.0") * sf
fn_4204 = Decimal("13123333.33333333") * sf

sr = arcpy.SpatialReference(2278)

print(sr.name)
print(sr.factoryCode)