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Laurence -<br>
<br>
Try the following for saving a shape layer as a valid GPX file
(tested on QGIS 1.7.4/Windows 7-64 bit):<br>
<ul>
<li>In the dialog "Layers" right click the name of the shape layer
you want the save as a gpx file. <br>
</li>
<li>Then left click on item "Save as...". This action will show a
new dialog: "Save vector layer as..."</li>
<li>Under "Format" : Choose "GPS eXchange format [GPX]"</li>
<li>Under "Save as": Write or browse the name for the new GPX file</li>
<li>Leave "Encoding" as "System"</li>
<li>Under CRS (upper dropdown): Choose "Selected CRS"</li>
<li>Under CRS (lower textbox): Browse the CRS to: "WGS 84" (It's <b>important</b>
you choose "WGS 84"; the GPX format support<b> only</b> this
CRS, but QGIS will happily write your data in any CRS) <br>
</li>
<li>If you have any unconventional GPX attributes in you data: Add
"GPX_USE_EXTENSIONS=yes" in the "Data source" textbox.</li>
<li>Click on OK.</li>
</ul>
Regards <br>
Bo Victor Thomsen<br>
Aestas-GIS<br>
Denmark<br>
<br>
Den 07-03-2012 10:14, Laurence Béchet skrev:
<blockquote cite="mid:4F5726E2.7000203@gmail.com" type="cite">
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Hi,<br>
Thank you for the suggestion.<br>
<br>
I did the test and of course the gpx created is not good, with a
list of error messages (not right values, like:<br>
Error at file
C:\[...]\xerces-c-3.1.1-x86-windows-vc-10.0\bin/newtiti.gpx, line
76, char 54<br>
Message: value '1730878.68283692' must be less than maxExclusive
facet value '180.0'<br>
<br>
If I start from an existing gpx file that passes the test (like
created with dnrgarmin or mapsource) and try to upload it within
Qgis, when I check the metadata of the layer property, the Layer
Spatial Reference System is not correct<br>
<font color="#cc0000"><b>+proj=longlat </b></font>+datum=WGS84
+no_defs<br>
<br>
If I upload in Qgis the same data created by dnrgarmin but under
the projected shapefile type, then the Layer Spatial Reference
System is correct<br>
<b><font color="#33cc00">+proj=tmerc</font></b> +lat_0=0
+lon_0=173 +k=0.9996 +x_0=1600000 +y_0=10000000 +ellps=GRS80
+towgs84=0,0,0,0,0,0,0 +units=m +no_defs<br>
<br>
<b>It's the general same issue: how do I force Qgis when uploading
or saving data in gpx file to use the correct Spatial reference
system (+proj)?</b><br>
<br>
How do other users do? Because I don't see the point of this
software if i cannot send my data from Qgis to my gps ...<br>
<br>
Thank you<br>
</blockquote>
<br>
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