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Hugo,<br>
<br>
I just tried your test case in the index page of Proj4js trunk and
it came up with the correct transformed coords. Do you have an
up-to-date version of Proj4js?<br>
<br>
Mike<br>
<br>
On 04/03/2011 9:21 AM, Hugo wrote:
<blockquote
cite="mid:AANLkTimthyM1_GCvb47Oh4McaRg0UJ=ZA7k1KU_RniDr@mail.gmail.com"
type="cite">Hello all,<br>
<br>
I'm developing an application using GeoExt and Openlayers. I'm
implementing a widget that will allow the user to enter
coordinates in several SRS and the map gets zoomed to it while, at
the same time, a vector feature is added to a specific layer.
However i'm getting strange values after reprojecting the
coordinates. I really need to use proj4js because some of the epsg
definitions for Portuguese SRS do not have the local
transformation parameters. For example, i wish to reproject from
EPSG:20791 to EPSG:900913. This is what i have done:<br>
<br>
1. Included proj4js-combined.js in the web page<br>
<br>
2. Created the SRS defintions:<br>
Proj4js.defs["EPSG:20791"] = "+proj=tmerc +lat_0=39.66666666666666
+lon_0=1 +k=1 +x_0=0 +y_0=0 +ellps=intl +pm=lisbon +units=m
+towgs84=-288.885,-91.744,+126.244,-1.691,0.410,-0.211,-4.598";<br>
<br>
Proj4js.defs["EPSG:900913"] = "+proj=merc +a=6378137 +b=6378137
+lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m
+nadgrids=@null +no_defs";<br>
<br>
3. Then i tried the following:<br>
<br>
var mercator = new OpenLayers.Projection("EPSG:900913");<br>
var hglipcc = new OpenLayers.Projection("EPSG:20791");<br>
xcoord = 19120.326567<br>
ycoord = -293121.903092<br>
var coordMarker = new OpenLayers.Geometry.Point(xcoord, ycoord);<br>
var coordMarkerRep = coordMarker.transform (hglipcc, etrs);<br>
var searchCoord = new OpenLayers.LonLat(xcoord, ycoord);<br>
var searchCoordRep = searchCoord.transform(hglipcc, mercator);<br>
<br>
Both returned the same wrong coordiantes: x= <span
class="objectBox objectBox-number ">-881483.8794817993 and y= </span><span
class="objectBox objectBox-number ">-7.081154551613622e-10 where
they should be x= -881320.416615 and y= 4442714.696599.<br>
<br>
Also, i have tried to use the projection definitions and
reproject transformation directly from Proj4js and the returned
results were exactly the same. <br>
<br>
Finally i have tried to reproject to EPSG:4326 and still, the
output coordinates are strange: it returned lon=</span><span
class="objectBox objectBox-number ">-7.918504416434706 and lat=0
where it should be lon=-7.917036 and lat=37.025879.<br>
<br>
Is this a known problem or is it something i'm doing wrong? Any
sugestions are more than welcome!<br>
Thanks in advance.<br>
<br>
Best regards,<br>
Hugo<br>
</span><span class="objectBox objectBox-number "><br>
</span><br>
<br>
<br>
<br>
<br>
3. Defined projections using new
OpenLayers.Projection('EPSG:xxxxx');<br>
<br>
4. the code used to reproject:<br>
<br>
var coordMarker = new OpenLayers.Geometry.Point(xcoord, ycoord);
//these coords in epsg 27492<br>
<br>
OpenLayers.Projection.transform(coordMarker, hg73ipcc, mercator);<br>
<br>
The coordinates introduced were x= 19300.924567 and
y=-293208.893092 and the output was x=-1897829.842341831 and
y=4442821.889195204. The expected output should be
x=-881320.416615 and y=4442714.696599<br>
<br>
I've tried to reproject from epsg:27492 to wgs84 and also got
wrong coordinates returned.<br>
Am i missing something here??? Any sugestions to solve this?<br
clear="all">
<br>
-- <br>
Hugo Martins<br>
LabNT - ISEGI UNL<br>
Campus de Campolide<br>
1070-312 Lisboa<br>
N 38°43'56.84", W 9°9'35.74"<br>
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