Geoscience Reference
In-Depth Information
1.5 Software Tools Covered in the Topic
The geospatial software used in our topic is exclusively free and open source. We will
introduce these tools and demonstrate their application and relevance to geospatial
data processing and analysis. Our intention is to present simple applications initially
and gradually expand the complexity of their usage. Our primary focus is on the
Geospatial Data Abstraction Library (GDAL/OGR), which remains one of the flag-
ship libraries of the Open Source Geospatial Foundation (OSGeo).
GDAL/OGR originated in the late 1990s as a C/C
geospatial transforma-
tion library that was developed by Frank Warmerdam. Warmerdam remained the
main developer until version 1.3.2, at which point the GDAL/OGR Project Manage-
ment Committee was established under the auspices of the Open Source Geospatial
Foundation (
http://osgeo.org
)
. Figure
1.2
presents a time-line depicting the package
releases and the development of the codebase since 1998 as presented by the Ohloh
(now openhub) on-line web service.
4
GDAL/OGR has now become the back-bone
of many of the OSGeo software packages, such as GRASS GIS, UMN MapServer,
QGIS, OpenEV, R Statistics, Orfeo Toolbox and pktools.
5
It is also used by a number
of other packages such as OSSIM, Cadcorp, Google Earth and Thuban. Due to it
being licensed under MIT, it can also be used in proprietary software packages, such
as ESRI's ArcGIS.
GDAL and its OGR Simple Features Library supports a wide array of spatial data
formats. In general, while GDAL refers to the package that includes both GDAL and
OGR, in this topic we refer to GDAL when we deal with raster processing and OGR
for the vector sections of the topic.
The default installation supports over 100 raster formats, among which the well
known GeoTIFF, ESRI E00 Grid, ERDAS (.Lan/.GIS) formats and Virtual Rasters.
OGR supports over 70 formats such as Spatialite, ESRI Shapefiles, KML/KMZ,
MapINFO, TIGER Files and GeoJSON etc. In some cases, GDAL/OGR provide
read-only support to the formats and for specific formats, such as NetCDF, it is often
required to customize the GDAL installation by linking additional libraries.
++
Fig. 1.2
Timeline of GDAL development in terms of number of code lines: code (
blue
), comments
(
gray
) and blanks (
green
)
5
for a more comprehensive list, see
http://trac.osgeo.org/gdal/wiki/SoftwareUsingGdal
.
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