[Mapserver-users] EXTENT and PROJECTION
Ethan Alpert
ealpert at digitalglobe.com
Mon Apr 26 13:26:35 EDT 2004
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Hello!
=20
=20
I spent yesterday scouring the archives of this email list trying to
find some info that would help me get a handle on displaying geotiff's
from my mapserver. I found plenty of posts that ask the same questions
but no responses. :/
=20
I promise to write up a summary if someone can point me in the right
direction.
=20
I've learned that if you bork the projection and extents in your mapfile
you end up with a nice blank image and no error message. I'm somewhat at
a loss as to how to go about debugging. So my question is given the
following info about a geotiff how do you experts go about setting up
PROJECTION and EXTENT?
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Here's the output of listgeo on my image:
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Geotiff_Information:
Version: 1
Key_Revision: 1.0
Tagged_Information:
ModelTiepointTag (2,3):
0 0 0
-5760628 4488331 0
ModelPixelScaleTag (1,3):
1001.042 1001.042 0
End_Of_Tags.
Keyed_Information:
GTModelTypeGeoKey (Short,1): ModelTypeProjected
GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
GTCitationGeoKey (Ascii,31): "TIFF 6.0, GeoTIFF Revision 1.0"
GeographicTypeGeoKey (Short,1): GCS_WGS_84
GeogCitationGeoKey (Ascii,157): "Actual datum is nonstandard,
based on sphere with radius 6370997 meters. Coded in GeoTIFF as WGS84
datum. The difference is not significant at this scale."
ProjectedCSTypeGeoKey (Short,1): User-Defined
PCSCitationGeoKey (Ascii,117): "Lambert Azimuthal Equal Area
projection with arbitrary plane grid; projection center 100.0 degrees W,
45.0 degrees N"
ProjCoordTransGeoKey (Short,1): CT_LambertAzimEqualArea
ProjLinearUnitsGeoKey (Short,1): Linear_Meter
ProjCenterLongGeoKey (Double,1): -100
ProjCenterLatGeoKey (Double,1): 45
End_Of_Keys.
End_Of_Geotiff.
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Projection Method: CT_LambertAzimEqualArea
ProjCenterLatGeoKey: 45.000000 ( 45d 0' 0.00"N)
ProjCenterLongGeoKey: -100.000000 (100d 0' 0.00"W)
ProjFalseEastingGeoKey: 0.000000 m
ProjFalseNorthingGeoKey: 0.000000 m
GCS: 4326/WGS 84
Datum: 6326/World Geodetic System 1984
Ellipsoid: 7030/WGS 84 (6378137.00,6356752.31)
Prime Meridian: 8901/Greenwich (0.000000/ 0d 0' 0.00"E)
Projection Linear Units: 9001/metre (1.000000m)
=20
PROJ.4 Definition: +proj=3Dlaea +lat_0=3D45.000000000 =
+lon_0=3D-100.000000000
+x_0=3D0.000 +y_0=3D0.000 +ellps=3DWGS84 +units=3Dm
=20
Corner Coordinates:
Upper Left (-5760628.000,4488331.000) (157d29'26.96"E, 40d47'
8.71"N)
Lower Left (-5760628.000,-2784239.130) (151d38'58.71"W,
4d43'23.63"N)
Upper Right (4279823.260,4488331.000) ( 4d 0'39.82"W, 53d59' 8.05"N)
Lower Right (4279823.260,-2784239.130) ( 61d 9'17.99"W, 11d18'
6.31"N)
Center (-740402.370, 852045.935) (110d51' 5.84"W, 52d12'27.42"N)
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Here's the borked map file I wrote:
=20
MAP
IMAGETYPE PNG
SIZE 600 600
SHAPEPATH "data"
EXTENT -5760628.000 -2784239.130 4279823.260 4488331.000
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PROJECTION
"proj=3Dlaea"
"lat_0=3D45.000000000"
"lon_0=3D-100.000000000"
"x_0=3D0.000"
"y_0=3D0.000"
"ellps=3DWGS84"
"units=3Dm"
END
=20
=20
=20
WEB
LOG "/var/www/ms.log"
END
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LAYER
NAME land
DATA landcvi0201.tif
STATUS DEFAULT
TYPE RASTER
=20
END
END=20
=20
I've tried all kinds of permutations. I'm assuming the extents should be
something other than the extents provided by listgeo but I haven't any
idea what they should be and would like to know what others do when the
get a new image to come up with appropriate extents.
=20
Thanks!
=20
-ethan
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE>Message</TITLE>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Dus-ascii">
<META content=3D"MSHTML 6.00.2800.1400" name=3DGENERATOR></HEAD>
<BODY>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2>Hello!</FONT></SPAN></DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2>I =
spent yesterday=20
scouring the archives of this email list trying to find some info that =
would=20
help me get a handle on displaying geotiff's from my mapserver. I found =
plenty=20
of posts that ask the same questions but no responses. =20
:/</FONT></SPAN></DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2>I =
promise to write=20
up a summary if someone can point me in the right =
direction.</FONT></SPAN></DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2>I've =
learned that if=20
you bork the projection and extents in your mapfile you end up with a =
nice blank=20
image and no error message. I'm somewhat at a loss as to how to go about =
debugging. So my question is given the following info about a geotiff =
how do you=20
experts go about setting up PROJECTION and EXTENT?</FONT></SPAN></DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2>Here's =
the output of=20
listgeo on my image:</FONT></SPAN></DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2>Geotiff_Information:<BR> Version: 1<BR> =
Key_Revision: 1.0<BR> =20
Tagged_Information:<BR> ModelTiepointTag=20
(2,3):<BR> =20
0 =
=20
0 =
=20
0<BR> =20
-5760628 =20
4488331 =20
0<BR> ModelPixelScaleTag=20
(1,3):<BR> =20
1001.042 =20
1001.042 =20
0<BR> End_Of_Tags.<BR> =20
Keyed_Information:<BR> GTModelTypeGeoKey=20
(Short,1): ModelTypeProjected<BR> =20
GTRasterTypeGeoKey (Short,1):=20
RasterPixelIsArea<BR> GTCitationGeoKey =
(Ascii,31):=20
"TIFF 6.0, GeoTIFF Revision 1.0"<BR> =20
GeographicTypeGeoKey (Short,1): =
GCS_WGS_84<BR> =20
GeogCitationGeoKey (Ascii,157): "Actual datum is nonstandard, based on =
sphere=20
with radius 6370997 meters. Coded in GeoTIFF as WGS84 datum. =
The=20
difference is not significant at this =
scale."<BR> =20
ProjectedCSTypeGeoKey (Short,1): =
User-Defined<BR> =20
PCSCitationGeoKey (Ascii,117): "Lambert Azimuthal Equal Area projection =
with=20
arbitrary plane grid; projection center 100.0 degrees W, 45.0 degrees=20
N"<BR> ProjCoordTransGeoKey (Short,1):=20
CT_LambertAzimEqualArea<BR> =
ProjLinearUnitsGeoKey=20
(Short,1): Linear_Meter<BR> =
ProjCenterLongGeoKey=20
(Double,1): -100<BR> ProjCenterLatGeoKey=20
(Double,1): 45<BR> =
End_Of_Keys.<BR> =20
End_Of_Geotiff.</FONT></SPAN></DIV>
<DIV> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial =
size=3D2>Projection Method:=20
CT_LambertAzimEqualArea<BR> ProjCenterLatGeoKey: 45.000000 ( =
45d 0'=20
0.00"N)<BR> ProjCenterLongGeoKey: -100.000000 (100d 0'=20
0.00"W)<BR> ProjFalseEastingGeoKey: 0.000000 =
m<BR> =20
ProjFalseNorthingGeoKey: 0.000000 m<BR>GCS: 4326/WGS 84<BR>Datum: =
6326/World=20
Geodetic System 1984<BR>Ellipsoid: 7030/WGS 84 =
(6378137.00,6356752.31)<BR>Prime=20
Meridian: 8901/Greenwich (0.000000/ 0d 0' 0.00"E)<BR>Projection =
Linear=20
Units: 9001/metre (1.000000m)</FONT></SPAN></DIV>
<DIV> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2>PROJ.4 =
Definition:=20
+proj=3Dlaea +lat_0=3D45.000000000 +lon_0=3D-100.000000000 +x_0=3D0.000 =
+y_0=3D0.000=20
+ellps=3DWGS84 +units=3Dm</FONT></SPAN></DIV>
<DIV> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2>Corner =
Coordinates:<BR>Upper Left =
(-5760628.000,4488331.000) =20
(157d29'26.96"E, 40d47' 8.71"N)<BR>Lower Left =20
(-5760628.000,-2784239.130) (151d38'58.71"W, =
4d43'23.63"N)<BR>Upper=20
Right (4279823.260,4488331.000) ( 4d 0'39.82"W, =
53d59'=20
8.05"N)<BR>Lower Right (4279823.260,-2784239.130) ( =
61d=20
9'17.99"W, 11d18' =
6.31"N)<BR>Center =20
(-740402.370, 852045.935) (110d51' 5.84"W,=20
52d12'27.42"N)<BR></FONT></SPAN></DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2>Here's =
the borked=20
map file I wrote:</FONT></SPAN></DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial =
size=3D2></FONT></SPAN><SPAN=20
class=3D727181517-26042004><FONT face=3DArial size=3D2>MAP<BR> =
IMAGETYPE=20
PNG<BR> SIZE 600 600<BR> SHAPEPATH "data"<BR> EXTENT=20
-5760628.000 -2784239.130 4279823.260 4488331.000</FONT></SPAN></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2> =
PROJECTION<BR> =20
"proj=3Dlaea"<BR> =20
"lat_0=3D45.000000000"<BR> =20
"lon_0=3D-100.000000000"<BR> =20
"x_0=3D0.000"<BR> =20
"y_0=3D0.000"<BR> =20
"ellps=3DWGS84"<BR> "units=3Dm"<BR> =20
END</FONT></SPAN></DIV>
<DIV> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2> =
WEB<BR> LOG "/var/www/ms.log"<BR> =20
END</FONT></SPAN></DIV>
<DIV> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2> =
LAYER<BR> NAME land<BR> DATA=20
landcvi0201.tif<BR> STATUS =
DEFAULT<BR> TYPE=20
RASTER</FONT></SPAN></DIV>
<DIV> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2> =
END<BR>END=20
<BR></FONT></SPAN></DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial size=3D2>I've =
tried all kinds=20
of permutations. I'm assuming the extents should be something other than =
the=20
extents provided by listgeo but I haven't any idea what they should be =
and would=20
like to know what others do when the get a new image to come up with =
appropriate=20
extents.</FONT></SPAN></DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2>Thanks!</FONT></SPAN></DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D727181517-26042004><FONT face=3DArial=20
size=3D2>-ethan</DIV></FONT></SPAN></BODY></HTML>
=00
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