Using Osmconvert with Python?

Question

I want to use osmconvert to parse down the size of my diff files for just the area I'm interested in because osmconvert is way faster than osm2pgsql, which loads the data.

When I call the command using os.system() like such:

cmd = r"""c:\temp\osmconvert.exe 770.osc.gz -b=1,1,3,3 -o=extract.o5m"""
os.system(cmd)

I get osmconvert error: cannot open file

When I run the same exact command from my command prompt in Windows 7, it runs fine. What is python doing to prevent this function from running? The 770.osc.gz file lives in the same directory as osmconvert.exe and the output extract.05m should populate in the same directory as the osmconvert.exe exists.

If I put the command in a batch file, it works, but I want to use python to download the file from the server so I can automate the updates of the database.

Answer 1

The 770.osc.gz file lives in the same directory as osmconvert.exe and the output extract.05m should populate in the same directory as the osmconvert.exe exists.

That's not what your code is saying. The code says "execute osmconvert.exe from inside c:\temp\ but read 770.osc.gz and write extract.o5m from the current working directory".

If you want everything to run inside c:\temp\ then you either have change to this directory before executing osmconvert or you have to preprend the path to every file you are passing to osmconvert.

Try this call instead:

cmd = r"""c:\temp\osmconvert.exe c:\temp\770.osc.gz -b=1,1,3,3 -o=c:\temp\extract.o5m"""