Hello,
I recently messaged about matching projection/transformations between GDAL/OSR
and ESRI (gdal-dev Digest, Vol 213, Issue 35).
I had two follow-up questions regarding transforming from a geographic CRS to a
projected CRS. When transforming from EPSG:6318 to a projected CRS EPSG:32015,
the point values I receive are different than in ESRI. My first question is,
when I am setting the
osr.SetAxisMappingStrategy(osr.OAMS_TRADITIONAL_GIS_ORDER) parameter for
EPSG:6318, why would the transformation points be different?
My second question is regarding the compound transformation that ESRI applies.
In this example ArcPy uses the "WGS_1984_(ITRF00)_To_NAD_1983_2011 +
NAD_1927_To_WGS_1984_3" transformation to project between EPSG:6318 and
EPSG:32015. Is there a way to replicate such a transformation using the python
GDAL/OSR libraries?
ESRI code:
arc_fromsr = arcpy.
SpatialReference
(6318)
arc_tosr = arcpy.
SpatialReference
(32015)
arcpoint = arcpy.
PointGeometry
(
arcpy.
Point
(
*
test_coords)
, arc_fromsr
)
transformers = arcpy.
ListTransformations
(
arc_fromsr, arc_tosr
)
# transformers[0] is WGS_1984_(ITRF00)_To_NAD_1983_2011 + NAD_1927_To_WGS_1984_3
new_arcpoint = arcpoint.
projectAs
(
arc_tosr, transformers
[0])
GDAL\OSR code:
to_nad = osr.
SpatialReference
()
to_nad.
ImportFromEPSG
(6318)
to_nad.
SetAxisMappingStrategy
(
osr.OAMS_TRADITIONAL_GIS_ORDER
)
final = osr.
SpatialReference
()
final.
ImportFromEPSG
(32015)
outpoint = ogr.
Geometry
(
ogr.wkbPoint
)
outpoint.
AddPoint_2D
(
*
test_coords)
outpoint.
AssignSpatialReference
(
to_nad
)
outpoint.
TransformTo
(
final
)
Input test coordinate: -73.964183, 40.785075
GDAL\OSR transformation output: 602119.3891505665, 286201.7616068426
ESRI\ArcPy transformation output: 602115.6116177095, 286190.512887311
Any help is again, greatly appreciated.
Sincerely,
Adam Gutonski
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