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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Jeff –<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Unfortunately, ESRI forgot about
projections when the shapefile format was created. There was a later
addition of a .prj file to go along with shapefiles and describe their
projection. If you have a .prj file of the same base name, you will have
that information – I expect you do not.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Without that information you’re down
to educated guesses. There are three likely candidates for US data –
geographic (unprojected) coordinates, a UTM projection, or a state plane
projection. If you are dealing with a multiple-state area, state plane is
unlikely.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Can you examine the coordinates in the
shapefile by either using the shpdump utility or loading the shapefile into a
GIS viewer and reading the coordinates? For <st1:place w:st="on">New
England</st1:place>, geographic coordinates will have X values ranging from
around -74 to -66, and Y values between 41 and 48. UTM coordinates
will range between X values of 200000 to 700000 and Y values between 4500000
and 5250000. As you can see, these are obviously different and easy to
distinguish.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>If you find you have values that don’t
match either of these, let us know what they are; the shpdump utility will give
you the bounding box of all shapes in the shapefile, and that’s a good
guide.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:33.0pt;text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
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style='font:7.0pt "Times New Roman"'>
</span></font></span></span></font><![endif]><font size=2 color=navy
face=Arial><span style='font-size:10.0pt;font-family:Arial;color:navy'>Ed<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Ed McNierney<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>TopoZone.com<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> UMN MapServer
Users List [mailto:MAPSERVER-USERS@LISTS.UMN.EDU] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Jeff Portwine<br>
<b><span style='font-weight:bold'>Sent:</span></b> Friday, January 21, 2005
10:49 AM<br>
<b><span style='font-weight:bold'>To:</span></b> MAPSERVER-USERS@LISTS.UMN.EDU<br>
<b><span style='font-weight:bold'>Subject:</span></b> [UMN_MAPSERVER-USERS]
projection questions</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Is there an easy way to figure out what projection my
shapefile was created with? I have a map of the <st1:place w:st="on">New
England</st1:place> area that was created in Microsoft's Map Point, and I am
more or less trying to re-create that map with mapserver. I
started with an outline of the United States and then set the extents to
display the area that I wanted, but the maps look very different and i'm
positive it's becuase I'm not using proper projections (I don't expect
the maps to look exactly alike of course, but the general shape should be
pretty close). I always use ogrinfo to get the extents and
see projection information of shapefiles that I've downloaded but more often
than not , the ogrinfo just returns: "Layer SRS WKT:
(Unknown)" instead of telling me the projection it was created
with.</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I also am not sure how to go about choosing my output
projection... I've been using EPSG:4269 because as I understand it that
is a midwest projection and when I first started playing with mapserver I was
making maps of <st1:State w:st="on"><st1:place w:st="on">Michigan</st1:place></st1:State>.
Anybody know a good source to look up what would be the best output projection
for different areas of the country/world? </span></font><o:p></o:p></p>
</div>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>As you can tell i'm really new to GIS and while I do
understand the idea of projections I just don't know anything about them or how
to apply them.</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thanks a lot,</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Jeff</span></font><o:p></o:p></p>
</div>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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