Python – Using ogr2ogr in Scripts

arcgis-proarcpygdalogrogr2ogr

I have been trying to figure out how to execute ogr2ogr to convert files in Python script. I got it to work in Jupyter notebook within ArcGIS Pro and in the terminal but not in Python scripts. Here's the code I used in the notebook.

import os,arcpy,shutil
from osgeo import ogr

abspath=os.path.abspath
abspath = os.path.abspath("__file__")
dname = os.path.dirname(abspath)
os.chdir(dname)

ProjectFolder=dname

arcpy.env.workspace=ProjectFolder
arcpy.env.overwriteOutput = True

! ogr2ogr siteboundary.shp Boundary.TAB

print("Conversion done,your file is located in "+ProjectFolder)

I searched a lot on how to use ogr commands in python script but had no luck. So I exported the notebook to a python script which was this.

import os,arcpy,shutil
from osgeo import ogr
from IPython import get_ipython

abspath=os.path.abspath
abspath = os.path.abspath(__file__)
dname = os.path.dirname(abspath)
os.chdir(dname)

ProjectFolder=dname

arcpy.env.workspace=ProjectFolder
arcpy.env.overwriteOutput = True

get_ipython().System("! ogr2ogr siteboundary.shp boundary.geojson")

print("Conversion done, your file is located in "+ProjectFolder)

But this script is giving me a 'NoneType' error

"Traceback (most recent call last):
File "S:\TOOLS\Scripts.test\CT429_ContamCertificates_GIS\Untitled1.py", line 24, in
get_ipython().System("! ogr2ogr siteboundary.shp boundary.geojson")
AttributeError: 'NoneType' object has no attribute 'System'"

So, I looked up nonetype error for system, found a really good resource "Any idea why IPython.get_ipython() is returning None?" but it's not working for me.

How can I do this?

I need this so that my team can run the Python scripts from the folder itself as that's more convenient.

Best Answer

I usually use subprocess to execute ogr2ogr.exe in windows cmd/terminal.

From geojson to shape:

import subprocess

command = [r"C:\OSGeo4W\bin\ogr2ogr.exe", r"C:\GIS\data\lan.shp", r"C:\GIS\data\lan.geojson"]

output, error  = subprocess.Popen(
                    command, universal_newlines=True,
                    stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()

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[GIS] Avoiding import arcpy error (RuntimeError: NotInitialized) when using IDLE

Looking at your posts here and on the ESRI Forums, I think you have some muddled environment settings.

You want to put C:\Python26\ArcGIS10.0 in your system PATH variable, that gets you to the correct executables from IDLE, PythonWin or the command line.

Your PYTHONPATH could be empty. Or, you could just include the 3 stanzas of your Desktop10.pth file: C:\Program Files (x86)\ArcGIS\Desktop10.0\bin C:\Program Files; (x86)\ArcGIS\Desktop10.0\arcpy; C:\Program Files (x86)\ArcGIS\Desktop10.0\ArcToolbox\Scripts--those paths will then take precedence over the the default search for modules (below the python.exe or pythonw.exe being called).

Finally, since you've uninstalled and installed several versions of Python. At this point, there should be nothing under the C:\Python26 folder except the ArcGIS10.0 folder of the ESRI provided Python 2.6.5 32-bit install. If there is a Lib file there it is a residual of an earlier install and will interfere. It would be a bigger problem if any or your prior Python26 installs were 64-bit.

Also, since you're on 64-bit Windows 7, the Registry path the to 32-bit Python keys are HKLM\SOFTWARE\Wow6432Node\Python If you have a HKLM\SOFTWARE\Python, they would be Keys for a 64-bit install. They also would interfere with the 32-bit install.

[GIS] Converting arcpy based python script to OGR for semi-automated Metadata creation

you're going in the right direction.

Unfortunately in OGR and GDAL there are no "List all datasets" functions available. This can be a bit of a pain, but it's easy enough to implement given a couple of provisos:

ogr.Open and gdal.Open will try and open any dataset, and will return None if it fails (note, this doesn't throw an exception)
Many datasets are actually made up of a number of different files on disk (such as ESRI Shapefiles or MapInfo TAB). OGR can be given any of these files and it will open the dataset (so, not just .shp, .shx and .dbf will all open the one shapefile) - this means we need to ignore them manually.

IGNORED_EXT = set([".mif", ".shx", ".dbf"]) #Map info files and ESRI shape files recognize
                                            #multiple extensions, so we ignore them
for root, dirs, files in os.walk(RootDirectory, topdown=False):
    for f in files:
        try:
            assert os.path.splitext(f)[1] not in IGNORED_EXT, "Ignoring %s" % f
            ds = ogr.Open(os.path.join(root, f))
            if ds is None:
                ds = gdal.Open(os.path.join(root, f))
            assert ds is not None, "%s is not compatible" % f
            print "Loaded %s successfully" % ds.GetName()
        except Exception, e:
            print "\t%s" % e

At this point GDAL and OGR datasets behave differently, e.g. in OGR there are Layers, in GDAL there are Bands. Try using isinstance to look at the feature type and then do something with it. For example:

isinstance(gdal.Open(ds), gdal.Dataset)

Lastly you may have some issues with getting the projection info from your data; while the ogr.Layer.GetSpatialRef() returns a osr.SpatialReference object, with gdal.Dataset.GetProjection() just returns a wkt string. To get the spatial reference object from a GDAL wkt, you can use (from the Spatial Notes blog):

srs = osr.SpatialReference()
srs.ImportFromWkt(ds.GetProjection())

The projection may not have a name, or even an associated EPSG code, but you should be able to find out all the information you need from the Spatial Reference object once you have it.

One last, last note: rather than using the standard xml library, take a look at lxml instead. Particularly the E-Factory example in the tutorial. It should make building the XML a lot easier.

Best Answer

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