Markus Metz
78a842ea73
libproj: do not free a pointer internal to a OGRSpatialReference; +safety check before calling OSRDestroySpatialReference()
|
7 years ago | |
|---|---|---|
| .. | ||
| Makefile | 8 years ago | |
| README.txt | 8 years ago | |
| convert.c | 7 years ago | |
| datum.c | 8 years ago | |
| desc.table | 13 years ago | |
| do_proj.c | 7 years ago | |
| ellipse.c | 8 years ago | |
| ftol.c | 14 years ago | |
| get_proj.c | 7 years ago | |
| local_proto.h | 12 years ago | |
| parms.table | 13 years ago | |
| projlib.dox | 7 years ago | |
| units.table | 13 years ago | |
README.txt
Projection string management: GRASS GIS relies on GDAL/PROJ.
The EPGS DB is transformed into suitable CSV data for GDAL/PROJ
according to this procedure:
http://svn.osgeo.org/metacrs/geotiff/trunk/libgeotiff/csv/README
The EPSG CSV files are used via GDAL/OGR API from
gdal-config --datadir
The datum shift grids are also used from GDAL/PROJ (proj-nad package).
TODO: It is recommended to rely on PROJ4's proj-nad package. For doing so,
there would be some changes needed to lib/proj/get_proj.c - the call
to pj_set_finder() should be removed so that PROJ looks in its default
locations for the files.
Function:
const char* pszDatumshiftfile = CPLFindFile( "gdal", "datum_shift.csv" );
##########
# EPSG code queries:
# printing all available datum shift codes
ogrinfo /usr/share/gdal/datum_shift.csv -al
ogrinfo /usr/share/gdal/gcs.csv -al
# selective printing
ogrinfo /usr/share/gdal/datum_shift.csv -al -where "SOURCE_CRS_CODE = '4156'" -al
ogrinfo /usr/share/gdal/gcs.csv -al -where "COORD_REF_SYS_NAME LIKE '%JT%'"
# print NAD file info
gdalinfo /usr/share/proj/hawaii
# query codes
gdalsrsinfo EPSG:5514
# transform between projections
gdaltransform -s_srs EPSG:4326 -t_srs "+proj=longlat +datum=nad27" --debug on
##########
# Testing: comparing results
# Testing using GDAL
PROJ_DEBUG=ON CPL_DEBUG=ON gdaltransform -s_srs EPSG:4326 -t_srs "+proj=longlat +datum=nad27"
-100 40
-99.9995941840488 39.9999941029394 0
# Testing using GRASS GIS
PROJ_DEBUG=ON CPL_DEBUG=ON m.proj proj_in="+init=epsg:4326" proj_out="+proj=longlat +datum=NAD27" coordinates=-100,40 -d
-99.99959418|39.99999410|0.00000000
The resulting values need to be identical (note: m.proj prints with less precision)
The EPGS DB is transformed into suitable CSV data for GDAL/PROJ
according to this procedure:
http://svn.osgeo.org/metacrs/geotiff/trunk/libgeotiff/csv/README
The EPSG CSV files are used via GDAL/OGR API from
gdal-config --datadir
The datum shift grids are also used from GDAL/PROJ (proj-nad package).
TODO: It is recommended to rely on PROJ4's proj-nad package. For doing so,
there would be some changes needed to lib/proj/get_proj.c - the call
to pj_set_finder() should be removed so that PROJ looks in its default
locations for the files.
Function:
const char* pszDatumshiftfile = CPLFindFile( "gdal", "datum_shift.csv" );
##########
# EPSG code queries:
# printing all available datum shift codes
ogrinfo /usr/share/gdal/datum_shift.csv -al
ogrinfo /usr/share/gdal/gcs.csv -al
# selective printing
ogrinfo /usr/share/gdal/datum_shift.csv -al -where "SOURCE_CRS_CODE = '4156'" -al
ogrinfo /usr/share/gdal/gcs.csv -al -where "COORD_REF_SYS_NAME LIKE '%JT%'"
# print NAD file info
gdalinfo /usr/share/proj/hawaii
# query codes
gdalsrsinfo EPSG:5514
# transform between projections
gdaltransform -s_srs EPSG:4326 -t_srs "+proj=longlat +datum=nad27" --debug on
##########
# Testing: comparing results
# Testing using GDAL
PROJ_DEBUG=ON CPL_DEBUG=ON gdaltransform -s_srs EPSG:4326 -t_srs "+proj=longlat +datum=nad27"
-100 40
-99.9995941840488 39.9999941029394 0
# Testing using GRASS GIS
PROJ_DEBUG=ON CPL_DEBUG=ON m.proj proj_in="+init=epsg:4326" proj_out="+proj=longlat +datum=NAD27" coordinates=-100,40 -d
-99.99959418|39.99999410|0.00000000
The resulting values need to be identical (note: m.proj prints with less precision)