Hi list,<br><br>I have some data that comes from different sources and are in different projections.<br>To use that data I need to reproject them to the same projection.<br><br>I'm going to use MapWindow GIS to show the layers.<br>
<br>I've got a XML (not GML) with a lot of info and one of that info is several coordinates that make up a polygon in epsg:28992 (Dutch RD).<br>I have a huge data set of shapefiles covering the entire area of The Netherlands. Those shapefiles are in a custom projection. <br>
And I want to use OpenStreetMap tiles as a background layers.<br>I have also a GPS receiver connected: WGS84<br><br>I'm using this proj4 string for Dutch RD:<br>+proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel +towgs84=565.04,49.91,465.84,-0.40939,0.35971,-1.86849,4.0772 +units=m +no_defs<br>
<br>I'm using this proj4 string for the OSM tiles:<br>+proj=merc +lon_0=0 +lat_ts=0 +x_0=0 +y_0=0 +a=6378137 +b=6378137 +units=m +no_defs<br><br>My WGS84 proj4 string is:<br>+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs<br>
<br>The custom projection used with the shapefiles is to line it up with Google Earth. That might be working but with OSM the shapefiles are about 10m off.<br>This is the algorithm used to convert the Dutch RD coordinates is:<br>
<pre>DPoint rd2LatLongGE(DPoint rd) //shp_order<br>{<br> // corrections for the rd coordinates for a better match with GE<br> const double Xc = 17.78369991;<br> const double Yc = 40.18290427;<br> <br> const double Xx = -0.0000749081;<br>
const double Xy = -0.0000128123;<br> const double Yx = -0.0000064425;<br> const double Yy = -0.0000846220;<br><br> return rd2LatLongWgs84(<br> DPoint(<br> rd.first + Xc + Xx * rd.first + Xy * rd.second<br> , rd.second + Yc + Yx * rd.first + Yy * rd.second<br>
)<br> );<br>}<br></pre><br>I think the best approach is to convert the shapefiles back to Dutch RD (their original projection) using a reversed version of the above algorithm.<br>Can I do that using ogr2ogr? What would the proj4 style project string be?<br>
Don't suggest to get the original shapefiles in DutchRD instead. I can't. People had to go to court to get this version (<a href="https://rejo.zenger.nl/inzicht/geografische-bestand-3d-shapes">https://rejo.zenger.nl/inzicht/geografische-bestand-3d-shapes</a> all in Dutch).<br>
<br>When I've got the shapefiles in Dutch RD I can check if it is aligning correctly with my Dutch RD polygon. If it is correct I will convert all data to epsg:900913 (Google Mercator).<br><br>So my main question is what is the proj4 style projection string of the algorithm and can I use it to reproject the shapefiles.<br>
<br>Thanks,<br><br>Paul<br>The Netherlands<br><br><br><br><br>