Revert fix to #22

The fix in #22 solved the problem at hand and doing what was expected from the specified parameters. Unfortunately it also removed the slightly hacky "feature" that makes the web mercator work in pj_transform. The web mercator is special since the latitude is computed on the ellipsoid, but behaves as if if was defined on a sphere. Hence it is problematic to change the ellipsoid parameters when using the web mercator, even though that is the geodetically correct thing to do. The web mercator is used in more or less any web mapping application and is thus one of the most frequently used transformations in PROJ. This justifies re-introducing the minor bug reported in #22. The problem will have to be taken care of properly when pj_transform is removed from the library in favour of the transformation pipelines based API.
OSGeo · Mar 1, 2018 · f41fad3 · f41fad3
1 parent 29874b8
commit f41fad3
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Showing 2 changed files with 9 additions and 24 deletions.
diff --git a/nad/proj_outIGNF.dist b/nad/proj_outIGNF.dist
@@ -1,16 +1,16 @@
 +init=./IGNF:NTFG +to +init=./IGNF:RGF93G
  3.300866856 43.4477976569 0.0000	3d18'0.915"E	43d26'52.077"N 0.000
 +init=./IGNF:LAMBE +to +init=./IGNF:LAMB93
- 600000.0000 2600545.4523  0.0000	652760.737	7033791.244 0.000
+ 600000.0000 2600545.4523  0.0000	652760.737	7033791.243 0.000
  135638.3592 2418760.4094  0.0000	187194.062	6855928.882 0.000
  998137.3947 2413822.2844  0.0000	1049052.258	6843776.562 0.000
- 600000.0000 2200000.0000  0.0000	649398.872	6633524.192 0.000
+ 600000.0000 2200000.0000  0.0000	649398.872	6633524.191 0.000
  311552.5340 1906457.4840  0.0000	358799.172	6342652.486 0.000
  960488.4138 1910172.8812  0.0000	1007068.686	6340907.237 0.000
  600000.0000 1699510.8340  0.0000	645204.279	6133556.746 0.000
-1203792.5981 626873.17210  0.0000	1238875.764	5057405.017 0.000
+1203792.5981 626873.17210  0.0000	1238875.764	5057405.016 0.000
 +init=./IGNF:LAMBE +to +init=./IGNF:GEOPORTALFXX
- 600000.0000 2600545.4523  0.0000	179040.148	5610495.276 0.000
+ 600000.0000 2600545.4523  0.0000	179040.148	5610495.275 0.000
  135638.3592 2418760.4094  0.0000	-303729.363	5410118.356 0.000
  998137.3947 2413822.2844  0.0000	592842.792	5410120.554 0.000
  600000.0000 2200000.0000  0.0000	179041.670	5209746.080 0.000
@@ -37,4 +37,4 @@
 2d20'11.7754730" 42d18'00.0824436" 0.0	260109.601	5009175.714 0.000
 9d32'12.6680218" 41d24'00.3542556" 0.0	1061637.534	4889066.592 0.000
 +init=./IGNF:RGR92 +to +init=./IGNF:REUN47
-3356123.5400 1303218.3090 5247430.6050	3353421.833	1304074.314 5248935.606
+3356123.5400 1303218.3090 5247430.6050	3353421.833	1304074.314 5248935.607
diff --git a/src/pj_transform.c b/src/pj_transform.c
@@ -748,32 +748,17 @@ int pj_datum_transform( PJ *srcdefn, PJ *dstdefn,
 /* -------------------------------------------------------------------- */
     if( srcdefn->datum_type == PJD_GRIDSHIFT )
     {
-        const char* srcnadgrids = pj_param(srcdefn->ctx, srcdefn->params,"snadgrids").s;
-
         pj_apply_gridshift_2( srcdefn, 0, point_count, point_offset, x, y, z );
         CHECK_RETURN(srcdefn);
 
-        /* If the gridlist has either "@null" or "null" as its only    */
-        /* grid we don't change the ellipsoid parameters, since the    */
-        /* datum shift to WGS84 was not performed in practice.         */
-        if ( srcnadgrids != NULL &&
-             strcmp("@null", srcnadgrids) && strcmp("null", srcnadgrids) ) {
-            src_a = SRS_WGS84_SEMIMAJOR;
-            src_es = SRS_WGS84_ESQUARED;
-        }
+        src_a = SRS_WGS84_SEMIMAJOR;
+        src_es = SRS_WGS84_ESQUARED;
     }
 
     if( dstdefn->datum_type == PJD_GRIDSHIFT )
     {
-        const char* dstnadgrids = pj_param(dstdefn->ctx, dstdefn->params,"snadgrids").s;
-        /* If the gridlist has either "@null" or "null" as its only    */
-        /* grid we don't change the ellipsoid parameters, since the    */
-        /* datum shift to WGS84 will not be performed.                 */
-        if ( dstnadgrids != NULL &&
-             strcmp("@null", dstnadgrids) && strcmp("null", dstnadgrids) ) {
-            dst_a = SRS_WGS84_SEMIMAJOR;
-            dst_es = SRS_WGS84_ESQUARED;
-          }
+        dst_a = SRS_WGS84_SEMIMAJOR;
+        dst_es = SRS_WGS84_ESQUARED;
     }
 
 /* ==================================================================== */