Displacement from coordinates

[Ed McNierney]

Nuri -

I used the US National Geodetic Survey's online calculator at http://www.ngs.noaa.gov/cgi-bin/utm_getut.prl and got different results for your first pair:

Northing: 4677368.307
Easting:   494970.715
Zone:		   31

The only datum choices are "NAD83" and "NAD27", and I got those results by choosing NAD83.

However, I also got exactly the same results using YOUR calculator and selecting the WGS84 datum.  Are you selecting the correct datum?  I selected WGS84 at the top, entered the first pair of coordinates, and got the answer above, not your answer below.

Are you using the calculator correctly?

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
Phone: +1 (978) 251-4242
Fax: +1 (978) 251-1396
ed at topozone.com

-----Original Message-----
From: N M [mailto:mapserver at hotmail.com] 
Sent: Monday, September 26, 2005 5:28 AM
To: Ed McNierney; MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] Displacement from coordinates

Hi,

To convert coordinates I use for example:

http://www.icc.es/geotex/egeoutmcatala2.html (a geodesic calculator)

An example of GPS coordinates and results are:

42º 14' 54.568" - 4677448.415
2º 56' 20.526" - 494971.3073

42º 14' 58.548" - 4677573.222
2º 57' 37.05" - 496724.1829

The correct containers are the little yellow squares and displaced are de blue ones:

http://www.nusvirtual.com/selectiva

The coordinates are form the first two containers in top rigth side of the map. I think you are right because I tried to place manually the containers and coordinates are displaced, so, how could I convert correctly GPS coordinates to UTM?

Thank you.

Nuri

>From: Ed McNierney <ed at TOPOZONE.COM>
>Reply-To: Ed McNierney <ed at TOPOZONE.COM>
>To: MAPSERVER-USERS at LISTS.UMN.EDU
>Subject: Re: [UMN_MAPSERVER-USERS] Displacement from coordinates
>Date: Fri, 23 Sep 2005 19:38:54 -0400
>
>Nuri -
>
>I agree with Steve - how exactly did you convert your GPS coordinates 
>to UTM coordinates?  What datum did you use, and what datum does the 
>rest of the map use?
>
>If you can give us a sample of the "GPS coordinates" and the UTM 
>output, we can check the conversion.
>
>	- Ed
>
>Ed McNierney
>President and Chief Mapmaker
>TopoZone.com / Maps a la carte, Inc.
>73 Princeton Street, Suite 305
>North Chelmsford, MA  01863
>Phone: +1 (978) 251-4242
>Fax: +1 (978) 251-1396
>ed at topozone.com
>
>-----Original Message-----
>From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] 
>On Behalf Of Steve Lime
>Sent: Friday, September 23, 2005 3:58 PM
>To: MAPSERVER-USERS at LISTS.UMN.EDU
>Subject: Re: [UMN_MAPSERVER-USERS] Displacement from coordinates
>
>I doubt it's a mapserver problem, most likely a problem the conversion 
>some place, or in the georeferencing of the map.
>
>Steve
>
> >>> SUBSCRIBE MAPSERVER-USERS Nuri <mapserver at HOTMAIL.COM> 09/23/05 
> >>> 7:55
>
> >>> AM >>>
>Hi,
>
>I created my own map and I inserted my coodinates. First of all I 
>translated my GPS coordinates to UTM coordinates and then to pixels to 
>insert it in a data base to place several symbols in my my.
>
>Al symbols have a displacement. As you can see in 
>www.nusvirtual.com/selectiva (click link to see de map) small yellow 
>rectangles are in the correct position but blue symbols are the 
>displaced ones.
>
>UTM coordinates are completely correct, I placed it manually over the 
>map but when mapserver place them they are incorrect.
>
>Someone could indicate me why appears this displacement?
>
>Thank you.
>
>Nuri

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