ogr2ogr apply sqlite dialect to multiple feature classes within a fgdb

Question

I have a quite many feature classes in a filegdb and they all have same data schema (same field names and etc).

I wanted to apply a single sqlite query and I am having hard time to make a loop command

ogr2ogr -f "filegdb" -a_srs epsg:3857 -dialect sqlite -sql "select scalecoords(geometry,0.0000000002), field1, field2, field3 from "FEATURE_CLASSES_WITHIN_A_FILEGDB" "inputGDB_Dir" "outputGDB_Dir"

what I did was simply applying

For /R %g in (inputGDB_Dir) do ogr2ogr -f "filegdb" -a_srs epsg:3857 -dialect sqlite -sql "select scalecoords(geometry,0.0000000002), field1, field2, field3" "inputGDB_Dir %g" "outputGDB_Dir"

and obviously, it does not work. I would like to know how to make a loop command using OGR2OGR

• Vince: Assuming your units are degrees, you're scaling your coordinates to twenty nanometers. If the value is applied to SRID, then you're scaling to subatomic precision (in Mercator, which is unreliable for distance even at kilometer scale).
• user30184: You should get what you want by using UNION in your SQL sqlitetutorial.net/sqlite-union. It may be somehow tricky to create the complete SQL with a script, though. It could be easier to make a script that runs ogr2ogr with -update and -update and -nln for each layer in your filegdb. The -nln parameter will be the same all the time for making that layer to gather all the data.

Answer 1

You can load your filegdb to python and then you can do something like this

import sys
for g in inputGDB:
 sys.call(Your shell command goes here)

By using sys.call() can execute your shell commands through python. As for loading filegdb to python you can use python libraries like fiona and ogr have a look and them.

• Pil Kwon: Can I use OGR2OGR command without using Python? Python seemed to be slower than just simple OGR2OGR command in Windows shell
• Asad Abbas: Yes you can do it using batch file, I never done this myself but you can refer stackoverflow.com/questions/2591758/batch-script-loop to get started with loops in batch script. Hope this answers your question