[OSRS-PROJ] Gradian Definitions

Paul Ramsey pramsey at refractions.net
Mon Jul 29 00:57:12 EDT 2002 

Attached find a patch against the 'nad/esri' file which converts the
gradians to degrees in the definitions and alters the longitude to be
relative to greenwich in the paris-origin cases. The affected
projections are

22391
22392
26191
26192
26193
27500
27581
27582
27583
27584
27591
27592
27593
27594
30491
30492
30591
30592

Those projections which are also in the 'nad/epsg' file should probably
also be modified.

P.

Craig Bruce wrote:
> 
> Gerald Evenden <gerald.evenden at verizon.net> wrote:
> 
> > The later, proj, definitioin is not in error unless one assumes that
> > the Greenwich origin is used.
> 
> In all likelihood, this is what everyone will assume.  Why would
> they assume otherwise?  Most users will never even see the parameter
> definitions.  It's best to avoid special cases.
> 
> > To use Greenwich data with proj one can merge the 2.33 correction into
> > the lon_0 factor.
> 
> The units also need to be translated from Gradians.  The 55° latitude
> figure goes through the middle of Great Britain and is nowhere near France.
> Translated, it would be 49.5°, which at least goes through France.
> 
> The programs that have extracted this information from the POSC EPSG
> database which defines them need to be modified to interpret the EPSG
> information in its full legal complexity.  (These same bugs have probably
> cropped up in countless other systems because the EPSG tables are so
> difficult to use.)
> 
> --------------------------+------------------------+--------------------------
> Dr. Craig S. Bruce        | Tel: 819-771-8303 x205 |             CubeWerx Inc.
> Senior Software Developer |   Home: 613-565-1344   |  Gatineau, Québec, Canada
> csbruce at cubewerx.com      | http://www.csbruce.com |  http://www.cubewerx.com/
> --------------------------+------------------------+--------------------------
>     "Everything should be built from the top down, except the first time."
> ----------------------------------------
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-------------- next part --------------
Index: esri
===================================================================
RCS file: /cvsroot/osrs/proj/nad/esri,v
retrieving revision 1.1
diff -u -r1.1 esri
--- esri	25 Jul 2002 20:44:55 -0000	1.1
+++ esri	29 Jul 2002 04:54:21 -0000
@@ -457,9 +457,9 @@
 # Carthage_UTM_Zone_32N
 <22332> +proj=utm +zone=32 +a=6378249.200 +b=6356515.000 +units=m 
 # Nord_Tunisie
-<22391> +proj=lcc +lat_1=40.000000000 +lat_2=0.000000000 +lat_0=40.000000000 +lon_0=11.000000000 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<22391> +proj=lcc +lat_1=36 +lat_2=0 +lat_0=36 +lon_0=9.9 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # Sud_Tunisie
-<22392> +proj=lcc +lat_1=37.000000000 +lat_2=0.000000000 +lat_0=37.000000000 +lon_0=11.000000000 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<22392> +proj=lcc +lat_1=33.3 +lat_2=0 +lat_0=33.3 +lon_0=9.9 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # Corrego_Alegre_UTM_Zone_23S
 <22523> +proj=utm +zone=23 +south +ellps=intl +units=m 
 # Corrego_Alegre_UTM_Zone_24S
@@ -689,11 +689,11 @@
 # Malongo_1987_UTM_Zone_32S
 <25932> +proj=utm +zone=32 +south +ellps=intl +units=m 
 # Nord_Maroc
-<26191> +proj=lcc +lat_1=37.000000000 +lat_2=0.000000000 +lat_0=37.000000000 +lon_0=-6.000000000 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<26191> +proj=lcc +lat_1=33.3 +lat_2=0 +lat_0=33.3 +lon_0=-5.4 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # Sud_Maroc
-<26192> +proj=lcc +lat_1=33.000000000 +lat_2=0.000000000 +lat_0=33.000000000 +lon_0=-6.000000000 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<26192> +proj=lcc +lat_1=29.7 +lat_2=0 +lat_0=29.7 +lon_0=-5.4 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # Sahara
-<26193> +proj=lcc +lat_1=29.000000000 +lat_2=0.000000000 +lat_0=29.000000000 +lon_0=-6.000000000 +x_0=1200000.000 +y_0=400000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<26193> +proj=lcc +lat_1=26.1 +lat_2=0 +lat_0=26.1 +lon_0=-5.4 +x_0=1200000.000 +y_0=400000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # Massawa_UTM_Zone_37N
 <26237> +proj=utm +zone=37 +ellps=bessel +units=m 
 # Minna_UTM_Zone_31N
@@ -1121,23 +1121,23 @@
 # Datum_73_UTM_Zone_29N
 <27429> +proj=utm +zone=29 +ellps=intl +units=m 
 # Nord_de_Guerre
-<27500> +proj=lcc +lat_1=55.000000000 +lat_2=0.000000000 +lat_0=55.000000000 +lon_0=6.000000000 +x_0=500000.000 +y_0=300000.000 +a=6376523.000 +b=6355862.933 +units=m 
+<27500> +proj=lcc +lat_1=49.5 +lat_2=0 +lat_0=49.5 +lon_0=7.73722916666667 +x_0=500000.000 +y_0=300000.000 +a=6376523.000 +b=6355862.933 +units=m 
 # NTF_Paris_France_I
-<27581> +proj=lcc +lat_1=55.000000000 +lat_2=0.000000000 +lat_0=55.000000000 +lon_0=0.000000000 +x_0=600000.000 +y_0=1200000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<27581> +proj=lcc +lat_1=49.5 +lat_2=0 +lat_0=49.5 +lon_0=2.33722916666667 +x_0=600000.000 +y_0=1200000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # NTF_Paris_France_II
-<27582> +proj=lcc +lat_1=52.000000000 +lat_2=0.000000000 +lat_0=52.000000000 +lon_0=0.000000000 +x_0=600000.000 +y_0=2200000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<27582> +proj=lcc +lat_1=46.8 +lat_2=0 +lat_0=46.8 +lon_0=2.33722916666667 +x_0=600000.000 +y_0=2200000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # NTF_Paris_France_III
-<27583> +proj=lcc +lat_1=49.000000000 +lat_2=0.000000000 +lat_0=49.000000000 +lon_0=0.000000000 +x_0=600000.000 +y_0=3200000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<27583> +proj=lcc +lat_1=44.1 +lat_2=0 +lat_0=44.1 +lon_0=2.33722916666667 +x_0=600000.000 +y_0=3200000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # NTF_Paris_France_IV
-<27584> +proj=lcc +lat_1=46.850000000 +lat_2=0.000000000 +lat_0=46.850000000 +lon_0=0.000000000 +x_0=234.358 +y_0=4185861.369 +a=6378249.200 +b=6356515.000 +units=m 
+<27584> +proj=lcc +lat_1=42.165 +lat_2=0 +lat_0=42.165 +lon_0=2.33722916666667 +x_0=234.358 +y_0=4185861.369 +a=6378249.200 +b=6356515.000 +units=m 
 # NTF_Paris_Nord_France
-<27591> +proj=lcc +lat_1=55.000000000 +lat_2=0.000000000 +lat_0=55.000000000 +lon_0=0.000000000 +x_0=600000.000 +y_0=200000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<27591> +proj=lcc +lat_1=49.5 +lat_2=0 +lat_0=49.5 +lon_0=2.33722916666667 +x_0=600000.000 +y_0=200000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # NTF_Paris_Centre_France
-<27592> +proj=lcc +lat_1=52.000000000 +lat_2=0.000000000 +lat_0=52.000000000 +lon_0=0.000000000 +x_0=600000.000 +y_0=200000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<27592> +proj=lcc +lat_1=46.8 +lat_2=0 +lat_0=46.8 +lon_0=2.33722916666667 +x_0=600000.000 +y_0=200000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # NTF_Paris_Sud_France
-<27593> +proj=lcc +lat_1=49.000000000 +lat_2=0.000000000 +lat_0=49.000000000 +lon_0=0.000000000 +x_0=600000.000 +y_0=200000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<27593> +proj=lcc +lat_1=44.1 +lat_2=0 +lat_0=44.1 +lon_0=2.33722916666667 +x_0=600000.000 +y_0=200000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # NTF_Paris_Corse
-<27594> +proj=lcc +lat_1=46.850000000 +lat_2=0.000000000 +lat_0=46.850000000 +lon_0=0.000000000 +x_0=234.358 +y_0=185861.369 +a=6378249.200 +b=6356515.000 +units=m 
+<27594> +proj=lcc +lat_1=42.165 +lat_2=0 +lat_0=42.165 +lon_0=2.33722916666667 +x_0=234.358 +y_0=185861.369 +a=6378249.200 +b=6356515.000 +units=m 
 # British_National_Grid
 <27700> +proj=tmerc +lat_0=49.000000000 +lon_0=-2.000000000 +k=0.999601 +x_0=400000.000 +y_0=-100000.000 +ellps=airy +units=m 
 # Palestine_1923_Palestine_Grid
@@ -1395,13 +1395,13 @@
 # TC_1948_UTM_Zone_40N
 <30340> +proj=utm +zone=40 +ellps=helmert +units=m 
 # Nord_Algerie_Ancienne
-<30491> +proj=lcc +lat_1=40.000000000 +lat_2=0.000000000 +lat_0=40.000000000 +lon_0=3.000000000 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<30491> +proj=lcc +lat_1=36 +lat_2=0 +lat_0=36 +lon_0=2.7 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # Sud_Algerie_Ancienne
-<30492> +proj=lcc +lat_1=37.000000000 +lat_2=0.000000000 +lat_0=37.000000000 +lon_0=3.000000000 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
+<30492> +proj=lcc +lat_1=33.3 +lat_2=0 +lat_0=33.3 +lon_0=2.7 +x_0=500000.000 +y_0=300000.000 +a=6378249.200 +b=6356515.000 +units=m 
 # Nord_Algerie
-<30591> +proj=lcc +lat_1=40.000000000 +lat_2=0.000000000 +lat_0=40.000000000 +lon_0=3.000000000 +x_0=500135.000 +y_0=300090.000 +ellps=clrk80 +units=m 
+<30591> +proj=lcc +lat_1=36 +lat_2=0 +lat_0=36 +lon_0=2.7 +x_0=500135.000 +y_0=300090.000 +ellps=clrk80 +units=m 
 # Sud_Algerie
-<30592> +proj=lcc +lat_1=37.000000000 +lat_2=0.000000000 +lat_0=37.000000000 +lon_0=3.000000000 +x_0=500135.000 +y_0=300090.000 +ellps=clrk80 +units=m 
+<30592> +proj=lcc +lat_1=33.3 +lat_2=0 +lat_0=33.3 +lon_0=2.7 +x_0=500135.000 +y_0=300090.000 +ellps=clrk80 +units=m 
 # Nord_Sahara_1959_UTM_Zone_29N
 <30729> +proj=utm +zone=29 +ellps=clrk80 +units=m 
 # Nord_Sahara_1959_UTM_Zone_30N

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