gdal

name	gdal
description	This skill should be used when working with GDAL command line tools for raster and vector geospatial processing. Covers inspection, reprojection, clipping, raster conversion, mosaics, tiling, rasterization, and COG creation.

GDAL Skill

Use GDAL command line tools for common raster and vector geospatial workflows.

Tools

Prefer the smallest tool that fits the task:

• gdalinfo
• ogrinfo
• gdalwarp
• gdal_translate
• gdalbuildvrt
• gdaltindex
• gdal_rasterize
• gdal2tiles.py
• ogr2ogr

If GDAL is not installed, ask the user to install it before continuing.

Workflow

1. Inspect first

gdalinfo INPUT.tif
ogrinfo INPUT.shp -so

2. Pick raster vs vector path

• Raster tasks: gdalwarp, gdal_translate, gdalbuildvrt, gdal_rasterize, gdal2tiles.py
• Vector tasks: ogr2ogr, ogrinfo, gdaltindex

3. Write a new output

• prefer new output files
• preserve CRS and nodata intentionally
• use compression for large rasters

4. Validate output

gdalinfo OUTPUT.tif
ogrinfo OUTPUT.geojson -so

Quick Reference

# Inspect
gdalinfo INPUT.tif
ogrinfo INPUT.shp -so

# Vector conversion and clipping
ogr2ogr -f GeoJSON -t_srs epsg:4326 OUTPUT.geojson INPUT.shp
gdaltindex -t_srs epsg:4326 -f GeoJSON OUTPUT_EXTENT.geojson INPUT_RASTER.tif
ogr2ogr -f GeoJSON -clipsrc OUTPUT_EXTENT.geojson OUTPUT_CLIPPED.geojson INPUT.shp

# Raster reprojection and clipping
gdalwarp -t_srs epsg:4326 INPUT.tif OUTPUT.tif
gdalwarp -cutline INPUT.shp -crop_to_cutline -dstalpha INPUT.tif OUTPUT.tif

# Raster conversion
gdal_translate -b 1 -b 2 -b 3 INPUT.tif OUTPUT.tif
gdal_translate -b 1 -b 2 -b 3 -of JPEG -outsize 400 0 INPUT.tif OUTPUT.jpg

# Mosaic and stack
gdalbuildvrt OUTPUT.vrt path/to/tiffs/*.tif
gdal_translate -co BIGTIFF=YES -co NUM_THREADS=ALL_CPUS -co COMPRESS=LZW -co PREDICTOR=2 OUTPUT.vrt OUTPUT.tif

# Rasterize and tile
gdal_rasterize -burn 1.0 -ot Byte -of GTiff -co COMPRESS=LZW -co BIGTIFF=YES INPUT.shp OUTPUT.tif
gdal2tiles.py -z 10-16 INPUT_BYTE.tif OUTPUT/

# COG
gdalwarp -co BIGTIFF=YES -co NUM_THREADS=ALL_CPUS -co COMPRESS=LZW -co PREDICTOR=2 -of COG INPUT.tif OUTPUT.tif

References

• references/gdal-recipes.md