[Qgis-user] Problem reprojecting a SHP

[Matt Boyd]

one of the more spatially aware Northern hemisphere people may
contradict me but.. if you look at..
http://en.wikipedia.org/wiki/File:Datum_Shift_Between_NAD27_and_NAD83.png
the amount of shift your seeing looks suspiciously in the range of the
difference between NAD27 and NAD83, are you positive your input data
are in NAD27 and that your using the correct translations through the
process?

Your use of "UTM WGS 84" doesn't seem correct. UTM implies an XY
coordinate system over a piece of the WGS84 spheroid and you need to
specify a zone as well.

good luck



On Sun, Jun 5, 2011 at 4:32 AM, Gerardo Jimenez <gejst5 at hotmail.com> wrote:
> Hi
> I have a dxf data whose coordinates are in UTM Nad27 zone 14q (14N for any
> GIS). I  reproject the data to UTM WGS 84 either with vector tools or save
> as options and data I have from a GPS do not match my vector layer. I posted
> this  also in the forum and followed the advise of building a KML from my
> original data.  Same thing. I made an experiment, same dxf, exported to
> shape, define UTM nad27 projection, and reproject to UTMwgs84 and build a
> kmz in ArcMap. QGis and ArcMap Nad 27 data do match perfectly. The wgs84
> data from QGIS and Arc Map differ about 80 meters (considerably if you want
> to use a vector layer displaying the streets of an entire city the size of
> Mexico City). The kmz from arcmap looks better in Google earth (streets do
> match better, not perfectly but better, the sat image) the the kml produced
> by QGis. So I wonder if anybody knows if I am doing something wrong or if
> the projection tools available in Qgis are working well.
> For those interested I Include the experiment in the following file
>
> http://hotfile.com/dl/119748524/923a1a6/Prueba.zip.html
>
> Thanks before hand
>
> Gerardo Jiménez Delgado
> Instituto de Investigaciones Antropológicas
> Universidad Nacional Autónoma de México
> Ciudad Universitaria s/n
> Coyoacan 04510 Mexico City
> Mexico 56 22 95 16
>
>
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