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I don't think that that is the problem here. The differences are
only a few centimeters, while errsors resulting from missing
+towgs84 parameters are in the order of 100 meters.<br>
<br>
Jan<br>
<br>
On 30-7-2013 11:57, Milo van der Linden (gmail) wrote:
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<div>Hello Jelmer,<br>
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1. I would strongly advice to transform everything to
wgs84 first.<br>
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2. wgs84 and etrs89 are based upon different
spheroids/datums. Transforming from wgs84 TO etrs89 will
not be correct if your etrs89 definition does not have
+towgs84 defined. And by default I believe it isn't.
Take a look at this ticket: <a moz-do-not-send="true"
href="http://trac.osgeo.org/proj/ticket/15">http://trac.osgeo.org/proj/ticket/15</a>
and see if it is of any help.<br>
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So, what I would do is:<br>
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epsg:28992 -> wgs84 (visual check) -> etrs89<br>
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Good luck!<br>
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<div class="gmail_quote">2013/7/30 Jelmer Baas <span dir="ltr"><<a
moz-do-not-send="true" href="mailto:baas@speerit.nl"
target="_blank">baas@speerit.nl</a>></span><br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
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<p><span lang="NL">Hello,</span></p>
<p><span lang="NL"> </span></p>
<p>For a new project we need to convert coordinates from
EPSG 28992 to EPSG 3044 with MapInfo, Oracle AND a few
Proj.4 programs (PostGIS, a custom DLL, Proj4js). The
problem we are having is that we're seeing some
shifted coordinates.</p>
<p> </p>
<p>First test point (in the Netherlands)</p>
<p><span style="font-family: "Courier New";">Origin
135745.924 517131.216</span></p>
<p><span style="font-family: "Courier New";">Proj4js
236345.39474983042 5839505.550959114</span></p>
<p><span style="font-family: "Courier New";">Postgis(1)
236345.390264227 5839505.55017783</span></p>
<p><span style="font-family: "Courier New";">Postgis(2)
236345.394817119 5839505.55055913</span></p>
<p><span style="font-family: "Courier New";"
lang="NL">MapInfo 236345.47
5839504.058</span></p>
<p><span style="font-family: "Courier New";"
lang="NL">CS2CSN 236345.39
5839505.55</span></p>
<p><span style="font-family: "Courier New";">DLL
old(4) 236345.396465174
5839505.54496813</span></p>
<p><span style="font-family: "Courier New";">DLL
new(3) 236345.390259674
5839505.55009311</span></p>
<p><span style="font-family: "Courier New";">Oracle
236345.49107424 5839504.12246656</span></p>
<p> </p>
<p>Test point (in Germany)</p>
<p><span style="font-family: "Courier New";">Origin
254870.45 415123.56</span></p>
<p><span style="font-family: "Courier New";">MapInfo
350265.960 5731670.259</span></p>
<p><span style="font-family: "Courier New";">Postgis(1)
350263.4072329 5731667.880
</span></p>
<p><span style="font-family: "Courier New";">Postgis(2)
350263.4132521 5731667.880
</span></p>
<p><span style="font-family: "Courier New";">DLL
new(3) 350263.407243136
5731667.88019826
</span></p>
<p><span style="font-family: "Courier New";">DLL
old(4) 350263.403514925
5731667.88565864
</span></p>
<p><span style="font-family: "Courier New";">Oracle(5)
350265.967728329 5731670.33312477
</span></p>
<p><span style="font-family: "Courier New";">CS2CS
350263.41 5731667.88 43.92 cs2cs
+init=EPSG:28992 +to +init=EPSG:3044</span></p>
<p> </p>
<p>It seems MapInfo and Oracle more-or-less agree, as do
all Proj.4-based products. I don’t know which are
“right”, meaning I also don’t know which ones are
wrong – let alone find the fault.
</p>
<p> </p>
<p>Hopefully someone can help me with this problem, or
at least point me in the right direction.</p>
<p> </p>
<p>(1): <span style="font-family: "Courier
New";">"+proj=sterea +lat_0=52.15616055555555
+lon_0=5.38763888888889 +k=0.9999079 +x_0=155000
+y_0=463000 +ellps=bessel
+towgs84=565.417,50.3319,465.552,-0.398957,0.343988,-1.8774,4.0725
+units=m +no_defs "</span></p>
<p>(2) Another server where I updated the
spatial_ref_system:
<span style="font-family: "Courier New";">"+proj=sterea
+lat_0=52.15616055555555 +lon_0=5.38763888888889
+k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel
+units=m
+towgs84=565.2369,50.0087,465.658,-0.406857330322398,0.350732676542563,-1.8703473836068,4.0812
+no_defs no_defs"</span></p>
<p>(3) A custom built DLL for usage in VB6.
"+proj=sterea +lat_0=52.15616055555555
+lon_0=5.38763888888889 +k=0.999908 +x_0=155000
+y_0=463000 +ellps=bessel +units=m
+towgs84=565.2369,50.0087,465.658,-0.406857330322398,0.350732676542563,-1.8703473836068,4.0812
+no_defs <>"</p>
<p>(4) Same DLL. “+proj=sterea +lat_0=52.15616055555555
+lon_0=5.38763888888889 +k=0.9999079 +x_0=155000
+y_0=463000 +ellps=bessel
+towgs84=565.417,50.3319,465.552,-0.398957,0.343988,-1.8774,4.0725
+units=m +no_defs <>”</p>
<p>(5)<span style="font-family: "Courier
New";"> select
sdo_cs.transform(SDO_GEOMETRY('POINT(254870.45
415123.56)', 90112),25832) from dual;</span></p>
<p>(5b) The Oracle definition contains some tags I
don’t see anywhere in Proj.4 (like the Bessel 1841
part): </p>
<p>PROJCS["Netherlands National System", GEOGCS [
"Netherlands Bessel", DATUM ["Netherlands Bessel",
SPHEROID ["Bessel 1841", 6377397.155, 299.1528128]],
PRIMEM [ "Greenwich", 0.000000 ], UNIT ["Decimal
Degree", 0.01745329251994330]], PROJECTION
["Stereographic"], PARAMETER ["Scale_Factor",
0.999908], PARAMETER ["Central_Meridian", 5.387639],
PARAMETER ["Latitude_Of_Origin", 52.156161], PARAMETER
["False_Easting", 155000.000000], PARAMETER
["False_Northing", 463000.000000], UNIT ["Meter",
1.000000000000]]
</p>
<p> </p>
<p>A side note is that transformation via my DLL doesn’t
work properly (i.e., coordinates are shifted tens of
meters), unless I *<b>first</b>* transform to WGS84
and then to 3044. I assume this is caused by an
easy-to-fix error, but I don’t know what that is.</p>
<p> </p>
<p>P.S.: PostGIS, Proj4JS and my epsg file are all
up-to-date.</p>
<p> </p>
<p>Thanks for any help,</p>
<p> </p>
<p><span lang="NL">With kind regards,</span></p>
<p><span lang="NL">Jelmer Baas</span></p>
<p><span lang="NL"> </span></p>
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