[GIS] FWTools ogr2ogr in Python

fwtoolsgdalpython

I am trying to convert MapINFO tabs to ESRI Shapefiles using FW Tools. I downloaded the tools and can run the FW Tools Shell and convert no problem:

ogr2ogr -f "ESRI Shapefile" E:\CABWorking\MapINFO2SHP\SHP\LincsBoundary.shp E:\CABWorking\MapINFO2SHP\MapINFOData\Lincolnshire.tab

In the shell you can type python and use the shell as a python interpreter. Awesome, but I need this to work as I want to convert a ton of MapINFO files at once.

My problem is: I can't figure out how to get the following code to work in a python environment. I've been searching all morning and just have no clue. Any help would be awesome!

Thanks!

Best Answer

In Python the os module provides a quick and dirty way to run a command line argument such as the one you posted as part of a larger script as outlined in the Python documentation

import os
command = "ogr2ogr -f \"ESRI Shapefile\" E:\\CABWorking\\MapINFO2SHP\\SHP\\LincsBoundary.shp E:\\CABWorking\\MapINFO2SHP\\MapINFOData\\Lincolnshire.tab"
os.system(command)

Note the use of backslashes to escape characters such as " and \ in the command string.

As I said, this is quick and dirty, the Pythonic way to do this is to use the Subprocess library which provides the same functionality but in a more stable framework, and with some more features:

import os
command = "ogr2ogr -f \"ESRI Shapefile\" E:\\CABWorking\\MapINFO2SHP\\SHP\\LincsBoundary.shp E:\\CABWorking\\MapINFO2SHP\\MapINFOData\\Lincolnshire.tab"
process = subprocess.Popen(cmd, stdout=subprocess.PIPE, creationflags=0x08000000) 
#the third command suppresses the opening of a new window for each process
#and can be removed if this is not the desired outcome
process.wait() #waits for one process to complete before launching another one

I used this answer to solve my issue. Thanks a ton @sgrieve. The final code ended up being:

import os, glob
inputDir = raw_input("==> ") # Had to have this code compatible with 2.3.4
outputDir = raw_input("==> ") # So that meant no easy file dialog boxes
TabFiles = glob.glob(str(inputDir) + '/*.tab')
for TabFile in TabFiles:
    TabFileName = TabFile[(TabFile.rfind("\\"))+1:(TabFile.rfind("."))]
    command = 'ogr2ogr -f "ESRI Shapefile" ' + outputDir + "/" + TabFileName + '.shp ' + TabFile
    os.system(command)

I'd then open the FWTools Shell, enter python and call the script with:

execfile("script")

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In general, don't use shell=True (especially with lists, see Getting output from Python script in Python tests

import subprocess
for subdir, dirs, files in os.walk(folder):
    for file in files:
       if file.endswith(".shp"):
           fileok=  os.path.abspath(os.path.join(subdir,file))      
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for file in files:
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works

Best Answer

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