[Mapserver-users] scale problem with latlong projection
Ed McNierney
ed@topozone.com
Thu, 22 May 2003 15:15:03 -0400
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fx -
=20
First, you should realize that a scalebar in any non-equidistant =
projection is not very meaningful. It's at best accurate only for =
certain measurements on the map.
=20
You should be using UNITS DD in your map, since your output projection =
units are decimal degrees. Your scalebar units will be in degrees =
(whatever that means <g>), too.
=20
- Ed
=20
Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA 01863
ed@topozone.com
(978) 251-4242=20
-----Original Message-----
From: fx gamoy [mailto:fx.gamoy@mapxplore.com]
Sent: Thursday, May 22, 2003 4:01 PM
To: mapserver-users@lists.gis.umn.edu
Subject: [Mapserver-users] scale problem with latlong projection
Hello,
i am trying to display some raster files in latlong projection =
(ellipsoid wgs84)
everything is fine but scale
$oMapSession->oMap->scale;
I obtain that france is about 80 meters width.. i don't think so.. :-)
any idea?
fx
http://www.mapxplore.com/
=20
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<DIV><SPAN class=3D953071419-22052003><FONT face=3DArial color=3D#0000ff =
size=3D2>fx=20
-</FONT></SPAN></DIV>
<DIV><SPAN class=3D953071419-22052003><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D953071419-22052003><FONT face=3DArial color=3D#0000ff =
size=3D2>First,=20
you should realize that a scalebar in any non-equidistant =
projection is not=20
very meaningful. It's at best accurate only for certain =
measurements on=20
the map.</FONT></SPAN></DIV>
<DIV><SPAN class=3D953071419-22052003><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D953071419-22052003><FONT face=3DArial color=3D#0000ff =
size=3D2>You=20
should be using UNITS DD in your map, since your output projection units =
are=20
decimal degrees. Your scalebar units will be in degrees (whatever =
that=20
means <g>), too.</FONT></SPAN></DIV>
<DIV><SPAN class=3D953071419-22052003><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D953071419-22052003> <FONT =
face=3DArial=20
color=3D#0000ff size=3D2>- Ed</FONT></SPAN></DIV>
<DIV><SPAN class=3D953071419-22052003></SPAN> </DIV>
<DIV><SPAN class=3D953071419-22052003><FONT size=3D2>Ed =
McNierney<BR>President and=20
Chief Mapmaker<BR>TopoZone.com / Maps a la carte, Inc.<BR>73 Princeton =
Street,=20
Suite 305<BR>North Chelmsford, MA =
01863<BR>ed@topozone.com<BR>(978)=20
251-4242 </FONT></DIV></SPAN>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> fx gamoy=20
[mailto:fx.gamoy@mapxplore.com]<BR><B>Sent:</B> Thursday, May 22, 2003 =
4:01=20
PM<BR><B>To:</B> mapserver-users@lists.gis.umn.edu<BR><B>Subject:</B>=20
[Mapserver-users] scale problem with latlong =
projection<BR><BR></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Hello,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>i am trying to display some raster =
files in=20
latlong projection (ellipsoid wgs84)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>everything is fine but =
scale</FONT></DIV>
<DIV><FONT face=3DArial =
size=3D2>$oMapSession->oMap->scale;</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I obtain that france is about 80 =
meters width.. i=20
don't think so.. :-)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>any idea?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>fx</FONT></DIV>
<DIV><FONT face=3DArial size=3D2><A=20
=
href=3D"http://www.mapxplore.com/">http://www.mapxplore.com/</A></FONT></=
DIV>
<DIV> </DIV></BLOCKQUOTE></BODY></HTML>
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