Changeset 68308

Timestamp:

Apr 25, 2016, 3:11:51 PM (8 years ago)

Author:

neteler

Message:

libproj: recognise NAD83(HARN) for NC; fix SIRGAS2000 datum; add explanations about datum management (contributed by Paul Kelly)

Location:

grass/trunk/lib

Files:

• gis/datum.table (modified) (4 diffs)
• gis/datumtransform.table (modified) (2 diffs)
• proj/convert.c (modified) (3 diffs)

grass/trunk/lib/gis/datum.table

@@ -1 @@
-# this file contains datum shift parameters,
+# Datum Transformation Parameter Lists for GRASS
+# (single 3-parameter datum transformation))
+#
+# This file contains datum shift parameters,
 # it supplies a datum database table for GRASS
 # format:
 # shortname "Full EPSG-style name" ellipsoid dx= dy= dz=
 #
-# where short name is a single word datum specifier,
-# Full EPSG-style name is the exact name used in the European 
-# Petroleum Survey Group (EPSG) database (enclosed in double quotes),
-# ellipsoid is the acronym of the ellipsoid used with this map datum, 
-# dx, dy and dz are the datum shift parameters.
-# no spaces allowed before or after the =.
+# where 
+# * short name is a single word datum specifier,
+# * Full EPSG-style name is the exact name used in the European 
+#   Petroleum Survey Group (EPSG) database (enclosed in double quotes),
+# * ellipsoid is the acronym of the ellipsoid used with this map datum, 
+#   (GRASS ellipsoid code, from ellipse.table)
+# * dx, dy and dz are the datum shift parameters that should cover the
+#   whole area the datum is used in.
+#   Note: no spaces allowed before or after the =.
 #
 # In general the 3-parameter transformation given in this file should
@@ -26 +32 @@
 #
 # Datum parameters for/from European Terrestrial Reference System ETRS89
-# are here: http://crs.ifag.de/crs_national.php
-#           http://crs.bkg.bund.de/crs-eu
+# are here: http://www.crs-geo.eu 
 
 # World Geodetic System 1984
@@ -37 +42 @@
 # North American 1983
 nad83   "North_American_Datum_1983"               grs80         dx=0.0      dy=0.0      dz=0.0
+nad83harn "NAD83_High_Accuracy_Reference_Network" grs80         dx=0.0      dy=0.0      dz=0.0
 # Tokyo datum mean
 tokyo  "Tokyo"                       bessel        dx=-148   dy=507    dz=685
@@ -92 +98 @@
 S_JTSK  "System_Jednotne_Trigonometricke_Site_Katastralni"      bessel  dx=589  dy=76   dz=480
 # http://spatialreference.org/ref/epsg/4674/
-Sistema_de_Referencia_Geocentrico_para_America_del_Sur_2000 "Sistema_de_Referencia_Geocentrico_para_America_del_Sur_2000"   grs80       dx=0        dy=0       dz=0
+sirgas2000 "Sistema_de_Referencia_Geocentrico_para_las_AmericaS_2000"   grs80       dx=0        dy=0       dz=0

grass/trunk/lib/gis/datumtransform.table

@@ -1 +1 @@
 # Datum Transformation Parameter Lists for GRASS
+# (allows multiple different sets of datum transformation parameters to be
+#  supplied for any datum)
 #
 # Line Format:
-# shortname "PROJ.4-style parameters" "Where Used" "Comment"
+# shortname "parameters" "Where Used" "Comment"
 #
-# 4 fields on each line, shortname should be already listed in datum.table
+# where
+# * parameters can be in any format accepted by PROJ.4, 
+#   so towgs84= 3 parameters or 7 parameters, or nadgrids=
+# * area of validity
+# * comment
+# Hence, 4 fields on each line, and shortname should be already
+# listed in datum.table.
 #
 # All but 1st field must be enclosed in quotes ("") An empty field can
@@ -10 +18 @@
 # much detail as possible for the user.
 #
-# datum.table only holds one 3-parameter transformation. Extra sets of 
+# Note: datum.table only holds one 3-parameter transformation. Extra sets of 
 # transformation parameters may be defined in this file for each datum
 # and will be presented to the user to select the most appropriate one for

grass/trunk/lib/proj/convert.c

@@ -745 +745 @@
  * datum that is already supported in GRASS. The number of entries must be even;
  * they are all in pairs. The first one in the pair is the non-standard name;
- * the second is the GRASS name. If a name appears more than once (as for
+ * the second is the GRASS/GDAL name. If a name appears more than once (as for
  * European_Terrestrial_Reference_System_1989) then it means there was more
  * than one non-standard name for it that needs to be accounted for. 
@@ -752 +752 @@
  * ogr/ogrfromepsg.cpp in the GDAL source tree! GRASS uses the EPSG
  * names in its WKT representation except WGS_1984 and WGS_1972 as
- * these shortened versions seem to be standard
+ * these shortened versions seem to be standard.
+ * Below order:
+ * the equivalent name comes first in the pair, and
+ * the EPSG name (as used in the GRASS datum.table file) comes second.
+ *
+ * The datum parameters are stored in
+ *   ../gis/datum.table           # 3 parameters
+ *   ../gis/datumtransform.table  # 7 parameters (requires entry in datum.table)
+ *
+ * Hint: use GDAL's "testepsg" to identify the canonical name, e.g.
+ *       testepsg epsg:4674
  */
 
@@ -788 +798 @@
     "South_American_1969",
     "South_American_Datum_1969",
-    "Sistema_de_Referencia_Geocentrico_para_las_AmericaS_2000",
-    "Sistema_de_Referencia_Geocentrico_para_America_del_Sur_2000",
     "ITRF_1992",
     "ITRF92",