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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:
    <blockquote
cite="mid:CANqqynmWF0nBvnfAQofeWoeir+Ye_+WpySADvOGTLFfBrXLdeQ@mail.gmail.com"
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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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        <br>
        <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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