<div>Hi Frank,</div>
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<div>the epsg definition is totally correct, sorry for a question like this. I've read some references, and if we said UTM ZONE 32N with the GRS80 ellipsoid, all the other parameter will set default.</div>
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<div>thanks frank.</div>
<div> </div>
<div>zhonghai<br><br> </div>
<div><span class="gmail_quote">On 7/12/06, <b class="gmail_sendername">Frank Warmerdam</b> <<a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a>> wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Zhonghai Wang wrote:<br>> Hi guys,<br>><br>> I noticed that some definitions for the EPSG codes in the epsg file is
<br>> not so clear, which means there are no parameters for the epsg codes,<br>> for example:<br>><br>> # ETRS89 / UTM zone 32N<br>> <25832> +proj=utm +zone=32 +ellps=GRS80 +units=m +no_defs <>
<br>><br>> the EPSG code for this one is 25832, but there are no other parameters<br>> any more, such as longitude, latitude, central meridian, false northing,<br>> false easting.....<br><br>Zhonghai,<br><br>I'm not sure what is wrong with the above definition. It is the preferred
<br>way of expressing UTM coordinate systems in PROJ.4, and is generally more<br>readable than the full "transverse mercator with parameters" definition<br>we see in WKT.<br><br>> and also this one:<br>><br>
> # NAD83(HARN)<br>> <4152> +proj=longlat +ellps=GRS80 +no_defs <><br>><br>> if the epsg code is defined like this, does it mean that the the EPSG<br>> code is not valid for use or is not defined?
<br><br>In this case we don't really understand what to do about the HARN datum<br>so we fallback to expressing things in terms of the underlying ellipsoid.<br><br>It can be used, but it won't do HARN specific datum corrections for you.
<br><br>Best regards,<br>--<br>---------------------------------------+--------------------------------------<br>I set the clouds in motion - turn up | Frank Warmerdam, <a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com
</a><br>light and sound - activate the windows | <a href="http://pobox.com/~warmerdam">http://pobox.com/~warmerdam</a><br>and watch the world go round - Rush | President OSGF, <a href="http://osgeo.org">http://osgeo.org
</a><br><br></blockquote></div><br>