topic Re: Find and fix images ith Spatial Reference Undefined. in Python Questions

Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Thu, 14 Jan 2016 22:02:12 GMT

I have a directory with 370 tifs. I just found out that a few, an unknown number, have the projection undefined, but they draw aligned with the know projection tifs, so no mystery there. I thought I could loop through a list of tifs in the folder and set the definition on the files missing, similar to https://community.esri.com/thread/13078 but wondered if I should add an "if" to check if the image is one of the ones with projection undefined. But what would be that test? Do you think the test would speed up execution or not?

Re: Find and fix images ith Spatial Reference Undefined.

DanPatterson_Retired — Thu, 14 Jan 2016 22:06:00 GMT

since you don't appear to be afraid of scripting, I will refer you to SpatialReference—Help | ArcGIS for Desktop

which contains all the appropriate information of coordinate systems and their associated properties. The code sample at the bottom will be of use to you

Re: Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Sat, 11 Dec 2021 20:48:30 GMT

I figure the code would be something like this, revised slightly from something I had laying around for fixing shapefiles, trying to remove the old style gp stuff. I'm still trying to figure out how I might test for projection undefined. but it might run just as fast without the test.

import arcgisscripting, sys, os, arcpy
from arcpy import env
# Load required toolboxes...  
#gp.AddToolbox("C:/Program Files/ArcGIS/ArcToolbox/Toolboxes/Data Management Tools.tbx")  
         
#workspace  
env.Workspace = "G:\\usgs_quads\\test"  
#coordsys = "C:\\Program Files\\ArcGISCoordinate Systems\\Projected Coordinate Systems\\National Grids\\British National Grid.prj"  
      
#List all features in  gp.workspace  
rasters = arcpy.ListRasters("*", "TIF")  
#raster = rasters.Next()


# get the coordinate system by describing a feature class
dsc = arcpy.Describe("YESMOWIT CANYON.tif")
coord_sys = dsc.spatialReference

  
for raster in rasters:  
     arcpy.defineprojection(raster, coord_sys)  
     print fc + " is defined."

Re: Find and fix images ith Spatial Reference Undefined.

DanPatterson_Retired — Thu, 14 Jan 2016 22:45:03 GMT

you did check the code sample in my previous post from the help file?. You want to get a list of them first ... before ... you define them. Just to make sure we are on the same page

ps you don't need arcgisscripting and check to see whether workspace is capitalized in env.w...

Re: Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Sat, 11 Dec 2021 20:48:32 GMT

Yes, the sample code was very helpful. Spent too much time looking through the Syntax and Properties section, when the sample had a clear example of the test. And yes lower case w on workspace was also needed. I couldn't figure out why my raster list seemed to be empty when it hit line 20.

This code worked on a sample data folder. Now I'll run it on the rest. I'm not sure if this testing if the coordinate system is undefined decreased run time or if I could even notice a difference with 370 files. Maybe 3000 files.

import sys, os, arcpy
from arcpy import env
# Load required toolboxes...  
#gp.AddToolbox("C:/Program Files/ArcGIS/ArcToolbox/Toolboxes/Data Management Tools.tbx")  
         
#workspace  
env.workspace = "G:\\usgs_quads\\test"  
#coordsys = "C:\\Program Files\\ArcGISCoordinate Systems\\Projected Coordinate Systems\\National Grids\\British National Grid.prj"  
      
#List all features in  gp.workspace  
rasters = arcpy.ListRasters("*", "TIF")  
#raster = rasters.Next()


# get the coordinate system by describing a feature class
dsc = arcpy.Describe("YESMOWIT CANYON.tif")
coord_sys = dsc.spatialReference

  
for raster in rasters:
    # Create the spatial reference object
    spatial_ref = arcpy.Describe(raster).spatialReference

    # If the spatial reference is unknown
    if spatial_ref.name == "Unknown":
     arcpy.DefineProjection_management(raster, coord_sys)  
     print raster + " is defined."

Re: Find and fix images ith Spatial Reference Undefined.

DanPatterson_Retired — Thu, 14 Jan 2016 23:31:56 GMT

I wouldnt worry about runtime... there are even clever shortcuts like making multiple copies of *.tfw world files to match *.tif files... and assuming you want the files to remain as separate entities initially at least... but lets not go there. Just let arcpy do its work

Re: Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Thu, 14 Jan 2016 23:46:37 GMT

Now I see where I picked up uppercase W on Workspace. I was looking at some old code examples from wayyyyyy back in 2010, back when everything started with creating a gp object. Then it was gp.Workspace. That's so six years ago.

Re: Find and fix images ith Spatial Reference Undefined.

DanPatterson_Retired — Thu, 14 Jan 2016 23:51:09 GMT

I hope you are ready for the transition to Python 3.x and arcgis pro ...

Re: Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Sat, 20 Feb 2016 00:24:25 GMT

A strange thing is happening today. I found another folder with a few undefined projection tifs in it. I changed my script so env.workspace = this new folder. But the script never gets any hits on the if spatial_ref.name == "Unknown": line. I stuck in a line around line 12 to print out my raster list and verified that I am getting the tifs into the list. Then I moved some of the known undefined spatial reference tifs into a test folder, and ran the script on the test folder. Same deal. Is there a kind of "undefined" that the spatial_ref.name == "Unknown": can't detect? In ArcCatalog, the properties of this tifs reveal that the Spatial Reference is <Undefined>

Re: Find and fix images ith Spatial Reference Undefined.

DanPatterson_Retired — Sat, 20 Feb 2016 00:37:42 GMT

your last two lines don't appear to be indented properly, correct and see what it does. Also, add a print statement above the if statement and actually print out the the name. make sure you str it so that it will catch None etc

Re: Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Sat, 11 Dec 2021 20:48:35 GMT

http://www.vidarholen.net/contents/interjections/ , indentation wasn't as important in VB, or Avenue, or AML, or CPL. But here, changing the indentation of the last two lines from two to a tab of four spaces didn't change the result. Still don't detect spatial reference == "unknown" and hit the defineProjection and the print raster + " is defined".

I had a hard time figuring out the print statement, but finally discovered it was simpler than I thought. Now I get a print out of spatial_ref string but I don't know what it means. In this test folder, ANDERSON LAKE.tif is defined as Washington State Plane S., while the rest are undefined.

for raster in rasters:
    # Create the spatial reference object
    spatial_ref = arcpy.Describe(raster).spatialReference
    #print "\n".join(raster).join(str(spatial_ref))
    #print "\n".join(raster),str(spatial_ref)
    #print "\n".join(raster)
    #print "\n".join(str(spatial_ref))
    #print (str(spatial_ref))
    print raster + " " + (str(spatial_ref))
    # If the spatial reference is unknown
    if spatial_ref.name == "Unknown":
        arcpy.DefineProjection_management(raster, coord_sys)  
        print raster + " is defined."

ANDERSON LAKE.tif <geoprocessing spatial reference object object at 0x113B3A88>
INDIAN ROCK.tif <geoprocessing spatial reference object object at 0x113B3AA0>
JENNIES BUTTE.tif <geoprocessing spatial reference object object at 0x113B3908>
JUNGLE BUTTE.tif <geoprocessing spatial reference object object at 0x113B3A88>

Re: Find and fix images ith Spatial Reference Undefined.

DanPatterson_Retired — Mon, 22 Feb 2016 21:20:34 GMT

Interjection #4. The result object in the print statement (line 9) is good, because it means that you obtained the spatial reference object.

SpatialReference—Help | ArcGIS for Desktop

From there, you can now navigate through and get its properties, like whether it if a geographic or projected coordinate system, its POSC code, its name and the like.

use spaces not tabs, 4 is generally the rule, but Guido says there are no rules, print has changed in python 3, get used to it justt put everything in brackets and learn the python mini-formatting language)

Re: Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Mon, 22 Feb 2016 21:58:14 GMT

Now I'm getting it. The print formatting stuff and the spatialReference object. From spatialReference.name, I can see that the problem rasters are set to Lambert_Conformal_Conic_2SP, but ArcDesktop thinks they are <Undefined>.

Re: Find and fix images ith Spatial Reference Undefined.

DanPatterson_Retired — Mon, 22 Feb 2016 22:04:12 GMT

Now do those files have a separate world file or is the coordinate system built-in? (assuming you are still talking about tiffs.... unfortunately tiff's are under the t's in this link...

Supported raster dataset file formats—Help | ArcGIS for Desktop

Re: Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Mon, 22 Feb 2016 22:37:23 GMT

The Stateplane and the undefined ones all have tfw files that contain 6 similar lines of numbers. The top and right numbers look like StatePlane, and they draw exactly where they are supposed to on a Wash. State Plane Data Frame, so I could just stop here and define the coordinate system of everything in the folder as State Plane.

I tried the trick in ArcCatalog to change the raster options to read the world file, but ArcCatalog still says they are undefined.

Re: Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Sat, 11 Dec 2021 20:48:38 GMT

Those Lambert_Conformal_Conic_2SP rasters stay stubbornly undefined. I modified my script to skip the if test for spacial ref unknown, and tried to just define the projection for everything in the folder:

for raster in rasters:
    # Create the spatial reference object
    spatial_ref = arcpy.Describe(raster).spatialReference
    print("{0} : {1}".format(raster, spatial_ref.name))
    # If the spatial reference is unknown
    #if spatial_ref.name == "Unknown":
    arcpy.DefineProjection_management(raster, coord_sys)  
    print raster + " is defined."

This runs, hits both print statements, the first print statement says the spatial ref is State_Plane but ArcCatalog still says they are undefined. In this test folder, only Anderson Lake is known to ArcCatalog as defined State Plane.

ANDERSON LAKE.tif : NAD_1983_StatePlane_Washington_South_FIPS_4602_Feet
ANDERSON LAKE.tif is defined.
INDIAN ROCK.tif : NAD_1983_StatePlane_Washington_South_FIPS_4602_Feet
INDIAN ROCK.tif is defined.
JENNIES BUTTE.tif : NAD_1983_StatePlane_Washington_South_FIPS_4602_Feet
JENNIES BUTTE.tif is defined.
JUNGLE BUTTE.tif : NAD_1983_StatePlane_Washington_South_FIPS_4602_Feet
JUNGLE BUTTE.tif is defined.

Re: Find and fix images ith Spatial Reference Undefined.

DanPatterson_Retired — Fri, 26 Feb 2016 02:54:12 GMT

You do refresh ArcCatalog between runs?

Re: Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Fri, 26 Feb 2016 17:37:57 GMT

I've tried refreshing ArcCatalog, restarting ArcCatalog, restarting the PC, and changing the ArcCatalog options to "Use world file" and back. State plane is a kind of Lambert_Conformal_Conic_2SP, so .spatialReference is getting part of the idea, but ArcCatalog is not. The bad tifs have a world file that is similar to the good tifs. Maybe I can attach one here.

Re: Find and fix images ith Spatial Reference Undefined.

DanPatterson_Retired — Fri, 26 Feb 2016 17:46:12 GMT

I am going to flag the expert on projections to help with this Melita Kennedy could you have a browse through this post and see if you can make any suggestions

Re: Find and fix images ith Spatial Reference Undefined.

PaulHuffman — Fri, 26 Feb 2016 19:32:09 GMT

ANDERSON LAKE is a good tif, INDIAN ROCK is a bad tif.