Geoscience Reference
In-Depth Information
By default,
gdalsrsinfo
provides the information in two formats: first in
proj4 and then in (pretty-print) well known text (WKT) format. The pretty-print
option provides a multi-line output. To get information about the longitude latitude
geographical coordinate system (EPSG:4326), simply type:
gdalsrsinfo EPSG:4326
PROJ.4 : '+proj=longlat +datum=WGS84 +no_defs '
OGC WKT :
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS 84",6378137,298.257223563,
AUTHORITY["EPSG","7030"]],
AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich",0,
AUTHORITY["EPSG","8901"]],
UNIT["degree",0.0174532925199433,
AUTHORITY["EPSG","9122"]],
AUTHORITY["EPSG","4326"]]
The proj4 and pretty-print output of the WKT formats are printed. The nested
system in longitude latitude has only to define a datum (WGS84), identified by
the authority EPSG:6326. The convention to choose the prime meridian (0) in
Greenwich is defined by authority EPSG:8901 and the authority for degree as a
unit is EPSG:9122. All together, the geographical coordinate system is defined as
EPSG:4326 as shown on the last line.
In contrast, a projected coordinate system such as UTM and Lambert Azimuthal
Equal Area, additionally requires a definition for the projection transform. This trans-
form is used to translate between linear positions (e.g., meter) and angular longi-
tude latitude positions. This is demonstrated for the European coordinate system
LAEA/ETRS89 (EPSG:3035) in which our forest type map flanders.tif is projected.
We will validate its coordinate system using the option
-V
:
gdalsrsinfo -V flanders.tif
Validate Succeeds
PROJ.4 : '+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000
ₒ
+y_0=3210000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m
ₒ
+no_defs '
OGC WKT :
PROJCS["ETRS89 / LAEA Europe",
GEOGCS["ETRS89",
DATUM["European_Terrestrial_Reference_System_1989",
SPHEROID["GRS 1980",6378137,298.2572221010002,
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