[mapserver-users] INSIDE Idaho

Tue Feb 9 06:44:10 PST 2010

Small progress this morning;

The extent numbers on my vector data seemed way off, so I switched to IDTM27, which uses easting=500000 and northing=100000, and the results were much closer.  There is a visible difference on the mapserver output... all the vector data is rendered "just a bit" west of the matching DRG data. Close enough for now.

Contents of my modified idtm83.wtk:

PROJCS["NAD_1983_Transverse_Mercator",
    GEOGCS["GCS_North_American_1983",
        DATUM["D_North_American_1983",
            SPHEROID["GRS_1980",6378137.0,298.257222101]],
        PRIMEM["Greenwich",0.0],
        UNIT["Degree",0.0174532925199433]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["False_Easting",500000.0],
    PARAMETER["False_Northing",100000.0],
    PARAMETER["Central_Meridian",-114.0],
    PARAMETER["Scale_Factor",0.9996],
    PARAMETER["Latitude_Of_Origin",42.0],
    UNIT["Meter",1.0]]

----- Original Message ----
From: Jon Miner <cp_n18 at yahoo.com>
To: mapserver-users at lists.osgeo.org
Sent: Tue, February 9, 2010 6:47:51 AM
Subject: Re: [mapserver-users] INSIDE Idaho

Bringing this back onto the mailing list....

Re: [mapserver-users] INSIDE Idaho...
From: "greg.luker at scu.edu.au" <greg.luker at scu.edu.au>...Add to Contacts 
To: Jon Miner <cp_n18 at yahoo.com> 
______________________________

Hi Jon,

I'm very much NOT a mapserver expert (a beginner in fact), but one thing I noticed (it might mean nothing) is:
UNIT["Degree",0.0174532925199433]]
I
realise that ogr is saying this, but I thought UTM projection unit is
metre not degree, and I'm guessing that number (0.0174532925199433) is
how many degrees in a metre at that latitude.
Also the gdalinfo is
listing the origin and pixel size in metres. One thing you could do is
just put one layer in a mapfile and set the mapfile projection to NAD83
(or whatever the epsg code is for that) to see if you can actually see
the data at all, and then project it into what you need, using "metres"
(or maybe "meters") as the unit, somehow. Sorry I can't help more, but
maybe this might point you in a useful direction.

Thanks,
Greg.

----- Forwarded Message ----
From: Jon Miner <cp_n18 at yahoo.com>
To: gluker at scu.edu.au
Sent: Mon, February 8, 2010 8:16:22 PM
Subject: Re: [mapserver-users] INSIDE Idaho

Hi Greg -

I've looked at the parameters... Here is the DRG file:

http://data.insideidaho.org/data2/24k/usgs/drg/idtm/quad/nocollar/archive/43112/cirbu3se_24k_usgs_drg.tgz

So I extract that file and then run gdalinfo on the tif file:

gdalinfo cirbu3se_24k_usgs_drg.tif 
Driver: GTiff/GeoTIFF
Files: cirbu3se_24k_usgs_drg.tif
Size is 4221, 5752
Coordinate System is `'
Origin = (590767.311137848766521,281203.236009103886317)
Pixel Size = (2.438400000000000,-2.438400000000000)
Metadata:
  TIFFTAG_SOFTWARE=Arc/Info
  TIFFTAG_XRESOLUTION=0.41
  TIFFTAG_YRESOLUTION=0.41
  TIFFTAG_RESOLUTIONUNIT=1 (unitless)
Image Structure Metadata:
  COMPRESSION=PACKBITS
  INTERLEAVE=BAND
Corner Coordinates:
Upper Left  (  590767.311,  281203.236) 
Lower Left  (  590767.311,  267177.559) 
Upper Right (  601059.798,  281203.236) 
Lower Right (  601059.798,  267177.559) 
Center      (  595913.554,  274190.398) 
...etc...

Note the blank "coordinate system" entry... Using values from http://spatialreference.org, I came up with the PROJECTION values in my map file, which seems to work, since mapserver renders the DRG. So far so good...

Next I download some vector data:

http://data.insideidaho.org/data/USCB/TIGER2000/archive/butte/roadsl_butte_uscb.tgz

and extract it, then check it with ogrinfo:

$ ogrinfo roadsl_butte_uscb.shp roadsl_butte_uscb -so
INFO: Open of `roadsl_butte_uscb.shp'
      using driver `ESRI Shapefile' successful.

Layer name: roadsl_butte_uscb
Geometry: Line String
Feature Count: 2596
Extent: (-113.641719, 43.284631) - (-112.694959, 44.233133)
Layer SRS WKT:
GEOGCS["GCS_North_American_1983",
    DATUM["North_American_Datum_1983",
        SPHEROID["GRS_1980",6378137.0,298.257222101]],
    PRIMEM["Greenwich",0.0],
    UNIT["Degree",0.0174532925199433]]
..etc..

If I'm not mistaken, I need to translate this to match the projection of the DRG file... I've been doing this with ogr2ogr:

ogr2ogr -t_srs idtm83.wkt -f "ESRI Shapefile" temp roadsl_butte_uscb.shp

where the idtm83.wkt contains:

PROJCS["NAD_1983_Transverse_Mercator",
    GEOGCS["GCS_North_American_1983",
        DATUM["D_North_American_1983",
            SPHEROID["GRS_1980",6378137.0,298.257222101]],
        PRIMEM["Greenwich",0.0],
        UNIT["Degree",0.0174532925199433]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["False_Easting",2500000.0],
    PARAMETER["False_Northing",1200000.0],
    PARAMETER["Central_Meridian",-114.0],
    PARAMETER["Scale_Factor",0.9996],
    PARAMETER["Latitude_Of_Origin",42.0],
    UNIT["Meter",1.0]]

ogrinfo on the new file reports:

Layer name: roadsl_butte_uscb
Geometry: Line String
Feature Count: 2596
Extent: (2528908.642544, 1342938.885743) - (2605077.684651, 1448186.034775)
Layer SRS WKT:
PROJCS["NAD_1983_Transverse_Mercator",
    GEOGCS["GCS_North_American_1983",
        DATUM["North_American_Datum_1983",
            SPHEROID["GRS_1980",6378137.0,298.257222101]],
        PRIMEM["Greenwich",0.0],
        UNIT["Degree",0.017453292519943295]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["False_Easting",2500000.0],
    PARAMETER["False_Northing",1200000.0],
    PARAMETER["Central_Meridian",-114.0],
    PARAMETER["Scale_Factor",0.9996],
    PARAMETER["Latitude_Of_Origin",42.0],
    UNIT["Meter",1.0]]

To me (as a programmer, not a map guru) everything seems to match up... Can you spot something that is not right?

Thanks

- Jon

________________________________
From: "greg.luker at scu.edu.au" <greg.luker at scu.edu.au>
To: Jon Miner <cp_n18 at yahoo.com>
Sent: Mon, February 8, 2010 5:50:47 PM
Subject: Re: [mapserver-users] INSIDE Idaho

Hi John,

According to this page: http://inside.uidaho.edu/tutorial/data/data.htm all INSIDE data:
"are available in Idaho Transverse Mercator (IDTM) projection.  Additionally, some data are available in Universal Transverse 
Mercator (UTM) projection." (UTM zone 11 or zone 12). Parameters are here:  http://inside.uidaho.edu/geodata/projparam.htm

Is this any help?

Thanks,
Greg.

Greg Luker
GIS Lab Manager
Southern Cross University
61 2 66203026

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