Script to merge geographical data using ogr2ogr

sh-merge.sh

#!/bin/bash

# Merge accepted files into one geojson using ogr2ogr. Supports DXF 2004 and later, Geojson and more
# http://www.gdal.org/ogr_formats.html
# This is a bit slow, but npm install geojson-merge seems to have trouble with big files
# Includes option to enable partial reprojection, dropping invalid coordinates, and also reprojects with custom PROJ.4 string
# Drops Z axis using -dim XY, but accepts Z axis features.

for f in *.dxf
do
    if [ ! -f merged.geojson ]; then
        ogr2ogr --config OGR_ENABLE_PARTIAL_REPROJECTION TRUE --config CPL_DEBUG ON -s_srs "+proj=sterea +lat_0=34.2 +lon_0=39.15 +x_0=28 +y_0=-42 +a=6378249.2 +b=6356515 +units=m +no_defs" -t_srs EPSG:4326 -a_srs EPSG:4326 -dim XY -dialect SQLITE -sql "SELECT e.layer, e.text, e.geometry FROM entities e WHERE ST_GeometryType(e.geometry) IN ('POINT', 'POINT Z', 'LINESTRING', 'LINESTRING Z', 'MULTILINESTRING', 'MULTILINESTRING Z', 'POLYGON', 'POLYGON Z', 'MULTIPOLYGON', 'MULTIPOLYGON Z');" -f "GeoJSON" merged.geojson "$f" -nln 'entities'
    else
        ogr2ogr --config OGR_ENABLE_PARTIAL_REPROJECTION TRUE --config CPL_DEBUG ON -s_srs "+proj=sterea +lat_0=34.2 +lon_0=39.15 +x_0=28 +y_0=-42 +a=6378249.2 +b=6356515 +units=m +no_defs" -t_srs EPSG:4326 -a_srs EPSG:4326 -dim XY -dialect SQLITE -sql "SELECT e.layer, e.text, e.geometry FROM entities e WHERE ST_GeometryType(e.geometry) IN ('POINT', 'POINT Z', 'LINESTRING', 'LINESTRING Z', 'MULTILINESTRING', 'MULTILINESTRING Z', 'POLYGON', 'POLYGON Z', 'MULTIPOLYGON', 'MULTIPOLYGON Z');" -f "GeoJSON" -update -append merged.geojson "$f" -nln 'entities'
    fi
done

# Usng GDAL Errors, many different submodules report errors using --config CP_DEBUG ON
# DXF OGRCT SQLITE DWG OGR GDAL GEOJSON GDALVectorTranslate OGR2SQLITE
# DXF: Unsupported HATCH boundary line type:4
# See more useful config options here https://trac.osgeo.org/gdal/wiki/ConfigOptions