GDAL/OGR

GDAL/OGR#

GDAL stands for Geospatial Data Abstraction Library. OGR doesn’t mean anything anymore. (see FAQ)

It is a translator library for raster and vector geospatial data formats. This means it can

  • get basic metadata of a vector or raster file

  • convert files to different formats, e.g. shapefile, geopackage, geojson

  • reproject files to different coordinate reference systems

  • merge multiple vector or raster files into one file

  • and much more.

For a full list of commands, take a look at the documentation. It can only be used from the command line. Generally,

Many (or basically all) GIS applications rely on GDAL, e.g. QGIS, ArcGIS, geopandas (python)

Usage#

You can find great video tutorials on how to use it in this YouTube Playlist by @makingsenseremotely6207

git_clone

On Windows: Open the OSGeo shell. It will not work in the normal command prompt.
On Mac/linux: Open the regular terminal/command line.

Execute one of the GDAL/OGR commands, e.g.

gdalinfo

Calling a command without any parameters will return the documentation of how to use it. More details and explanations are given in the online documentation, e.g. on gdalinfo

Usage: gdalinfo [--help-general] [-json] [-mm] [-stats | -approx_stats] [-hist] [-nogcp] [-nomd]
                [-norat] [-noct] [-nofl] [-checksum] [-proj4]
                [-listmdd] [-mdd domain|`all`] [-wkt_format WKT1|WKT2|...]*
                [-sd subdataset] [-oo NAME=VALUE]* [-if format]* datasetname

FAILURE: No datasource specified.

The parameters given in brackets are optional, the ones without are mandatory. For the command gdalinfo, this means that the parameter datasetname needs to be given. For example, executing gdalinfo with a path to a raster file will return the files’s metadata. Try it using the data from the second assignment.

gdalinfo ./data/n45_e013_1arc_v3_sub.tif
Driver: GTiff/GeoTIFF
Files: ./data/n45_e013_1arc_v3_sub.tif
Size is 5727, 2461
Coordinate System is:
GEOGCRS["WGS 84",
    ENSEMBLE["World Geodetic System 1984 ensemble",
        MEMBER["World Geodetic System 1984 (Transit)"],
        MEMBER["World Geodetic System 1984 (G730)"],
        MEMBER["World Geodetic System 1984 (G873)"],
        MEMBER["World Geodetic System 1984 (G1150)"],
        MEMBER["World Geodetic System 1984 (G1674)"],
        MEMBER["World Geodetic System 1984 (G1762)"],
        MEMBER["World Geodetic System 1984 (G2139)"],
        ELLIPSOID["WGS 84",6378137,298.257223563,
            LENGTHUNIT["metre",1]],
        ENSEMBLEACCURACY[2.0]],
    PRIMEM["Greenwich",0,
        ANGLEUNIT["degree",0.0174532925199433]],
    CS[ellipsoidal,2],
        AXIS["geodetic latitude (Lat)",north,
            ORDER[1],
            ANGLEUNIT["degree",0.0174532925199433]],
        AXIS["geodetic longitude (Lon)",east,
            ORDER[2],
            ANGLEUNIT["degree",0.0174532925199433]],
    USAGE[
        SCOPE["Horizontal component of 3D system."],
        AREA["World."],
        BBOX[-90,-180,90,180]],
    ID["EPSG",4326]]
Data axis to CRS axis mapping: 2,1
Origin = (13.453194444444444,46.059583333333329)
Pixel Size = (0.000277777777778,-0.000277777777778)
Metadata:
  AREA_OR_POINT=Point
  DTED_CompilationDate=0002
  DTED_DataEdition=02
  DTED_DigitizingSystem=SRTM
  DTED_HorizontalAccuracy=0009
  DTED_HorizontalDatum=WGS84
  DTED_MaintenanceDate=0000
  DTED_MaintenanceDescription=0000
  DTED_MatchMergeDate=0000
  DTED_MatchMergeVersion=A
  DTED_NimaDesignator=DTED2
  DTED_OriginLatitude=0450000N
  DTED_OriginLongitude=0130000E
  DTED_Producer=USCNIMA
  DTED_RelHorizontalAccuracy=NA
  DTED_RelVerticalAccuracy=0005
  DTED_SecurityCode_DSI=U
  DTED_SecurityCode_UHL=U
  DTED_UniqueRef_DSI=F02 091
  DTED_UniqueRef_UHL=F02 091
  DTED_VerticalAccuracy_ACC=0004
  DTED_VerticalAccuracy_UHL=0004
  DTED_VerticalDatum=E96
Image Structure Metadata:
  COMPRESSION=DEFLATE
  INTERLEAVE=BAND
  PREDICTOR=2
Corner Coordinates:
Upper Left  (  13.4531944,  46.0595833) ( 13d27'11.50"E, 46d 3'34.50"N)
Lower Left  (  13.4531944,  45.3759722) ( 13d27'11.50"E, 45d22'33.50"N)
Upper Right (  15.0440278,  46.0595833) ( 15d 2'38.50"E, 46d 3'34.50"N)
Lower Right (  15.0440278,  45.3759722) ( 15d 2'38.50"E, 45d22'33.50"N)
Center      (  14.2486111,  45.7177778) ( 14d14'55.00"E, 45d43' 4.00"N)
Band 1 Block=5727x1 Type=Int16, ColorInterp=Gray
  NoData Value=-32767

Adding the optional flag -json will return the same information but formatted in json format.

gdalinfo ./data/n45_e013_1arc_v3_sub.tif -json

If you get error messages, these could be the reasons#

  • Avoid file paths containing whitespaces. If you cannot avoid it, you need to put the file path in quotes “file_path”.

  • Sometimes the order of the parameters plays a role. Check it in the documentation.

  • Are the file paths correct? Any typos? Are you in the right directory relativ to the file path?

  • If the command cannot be found, are you in the OSGeo Shell?

Most frequently used GDAL/OGR commands#

This is a short list of the most frequently used GDAL/OGR commands in daily GIS usage. But there are a lot more as you can see in the documentation

Feel free to fork this repository, add the missing information in the table and create a merge request. All information can be found at https://gdal.org.

Command

Purpose

gdalinfo

ogrinfo

gdal_translate

gdalwarp

gdalbuildvrt

gdal_merge

ogr2ogr

Resources#

Contents