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I used the original code from the question (which should work, the question wasn't about the actual code) and found a bug. This edit fixes the bug.

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edit approved Feb 26, 2017 at 6:44

Tiago Fassoni

The basic script in order to iterate recursively over sub-folders and merge all shapefiles into single one is:

#!/bin/bash
consolidated_file="./consolidated.shp"
for i in $(find . -name '*.shp'); do
    if [ ! -f "$file""$consolidated_file" ]; then
        # first file - create the consolidated output file
        ogr2ogr -f "ESRI Shapefile" $consolidated_file $i
    else
        # update the output file with new file content
        ogr2ogr -f "ESRI Shapefile" -update -append $consolidated_file $i
    fi
done

Hoverer in vertaully all examples around the web I noticed that for the case where I update the output file, -nln tag is added, for example:

ogr2ogr -f "ESRI Shapefile" -update -append $consolidated_file $i -nln merged

According to the documentation it says:

Assign an alternate name to the new layer

And I noticed it creates a temporary shapefile called "merged", and in the end of the loop the file is identical to the last shapefile I merged.

I don't understand why I need this? Because I succeeded to merge successfully without this tag.

The basic script in order to iterate recursively over sub-folders and merge all shapefiles into single one is:

#!/bin/bash
consolidated_file="./consolidated.shp"
for i in $(find . -name '*.shp'); do
    if [ ! -f "$file" ]; then
        # first file - create the consolidated output file
        ogr2ogr -f "ESRI Shapefile" $consolidated_file $i
    else
        # update the output file with new file content
        ogr2ogr -f "ESRI Shapefile" -update -append $consolidated_file $i
    fi
done

Hoverer in vertaully all examples around the web I noticed that for the case where I update the output file, -nln tag is added, for example:

ogr2ogr -f "ESRI Shapefile" -update -append $consolidated_file $i -nln merged

According to the documentation it says:

Assign an alternate name to the new layer

And I noticed it creates a temporary shapefile called "merged", and in the end of the loop the file is identical to the last shapefile I merged.

I don't understand why I need this? Because I succeeded to merge successfully without this tag.

The basic script in order to iterate recursively over sub-folders and merge all shapefiles into single one is:

#!/bin/bash
consolidated_file="./consolidated.shp"
for i in $(find . -name '*.shp'); do
    if [ ! -f "$consolidated_file" ]; then
        # first file - create the consolidated output file
        ogr2ogr -f "ESRI Shapefile" $consolidated_file $i
    else
        # update the output file with new file content
        ogr2ogr -f "ESRI Shapefile" -update -append $consolidated_file $i
    fi
done

Hoverer in vertaully all examples around the web I noticed that for the case where I update the output file, -nln tag is added, for example:

ogr2ogr -f "ESRI Shapefile" -update -append $consolidated_file $i -nln merged

According to the documentation it says:

Assign an alternate name to the new layer

And I noticed it creates a temporary shapefile called "merged", and in the end of the loop the file is identical to the last shapefile I merged.

I don't understand why I need this? Because I succeeded to merge successfully without this tag.

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asked Jan 4, 2017 at 7:52

michael

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ogr2ogr merge multiple shapefiles: What is the purpose of -nln tag?

The basic script in order to iterate recursively over sub-folders and merge all shapefiles into single one is:

#!/bin/bash
consolidated_file="./consolidated.shp"
for i in $(find . -name '*.shp'); do
    if [ ! -f "$file" ]; then
        # first file - create the consolidated output file
        ogr2ogr -f "ESRI Shapefile" $consolidated_file $i
    else
        # update the output file with new file content
        ogr2ogr -f "ESRI Shapefile" -update -append $consolidated_file $i
    fi
done

Hoverer in vertaully all examples around the web I noticed that for the case where I update the output file, -nln tag is added, for example:

ogr2ogr -f "ESRI Shapefile" -update -append $consolidated_file $i -nln merged

According to the documentation it says:

Assign an alternate name to the new layer

And I noticed it creates a temporary shapefile called "merged", and in the end of the loop the file is identical to the last shapefile I merged.

I don't understand why I need this? Because I succeeded to merge successfully without this tag.