I'm not sure how this works in gdal/ogr, but proj library uses the tag
before the ":" as the name of a file containing the projection data.
gdal/ogr may use an different database of projection information.
Anyway, the following show these projection definitions:
$ grep "Michigan GeoRef" /usr/share/proj/esri
# NAD 1927 Michigan GeoRef Feet US
<102120> +proj=omerc +lat_0=45.30916666666666 +lonc=-86
+alpha=337.255555555556 +k=0.9996 +x_0=2546731.495961392
+y_0=-4354009.816002033 +ellps=clrk66 +datum=NAD27
+to_meter=0.3048006096012192 no_defs <>
# NAD 1983 Michigan GeoRef Feet US
<102121> +proj=omerc +lat_0=45.30916666666666 +lonc=-86
+alpha=337.255555555556 +k=0.9996 +x_0=2546731.495961392
+y_0=-4354009.816002033 +ellps=GRS80 +datum=NAD83
+to_meter=0.3048006096012192 no_defs <>
# NAD 1927 Michigan GeoRef Meters
<102122> +proj=omerc +lat_0=45.30916666666666 +lonc=-86
+alpha=337.255555555556 +k=0.9996 +x_0=2546731.496 +y_0=-4354009.816
+ellps=clrk66 +datum=NAD27 +units=m no_defs <>
# NAD 1983 Michigan GeoRef Meters
<102123> +proj=omerc +lat_0=45.30916666666666 +lonc=-86
+alpha=337.255555555556 +k=0.9996 +x_0=2546731.496 +y_0=-4354009.816
+ellps=GRS80 +datum=NAD83 +units=m no_defs <>
So you might be able to reference one of these projections via
ESRI:102123 for example for the last projection listed above. Or you
might be able to copy one or all of these projection definitions to the
/usr/shar/proj/epsg file and rename the number to an appropriate EPSG
definition, then try referencing if from gdal/ogr
-Steve
On 6/26/2011 11:06 AM, Howard Y wrote:
All,
I was wondering if there has been any progress in addressing the various
problems associated with correctly projecting to and from Michigan Oblique
Mercator (EPSG:3078 and its brethren), as brought up in tickets 2475, 3038,
and 3311, among others.
As you may know, the State of Michigan, USA, distributes GIS vector and
raster files in the Michigan Oblique Mercator ("Michigan GeoRef")
projection. Commercial software packages from ESRI and others seem to be
able to handle data projected in this format, but open source software
packages that depend on GDAL/OGR routines do not seem to be able, for the
most part, to do so. I've found QGIS and MapWindow to be among the software
packages that cannot successfully handle Michigan GeoRef using existing
definitions for EPSG:3078 and its kin. (The only exception seems to be
uDig. For some reason, uDig appears to be able to bring in a Michigan
GeoRef shapefile and successfully reproject it to Michigan State Plane
Coordinates, for example.)
I feel that this problem may be the single biggest factor that stands in the
way of wider adoption of open source GIS software in Michigan. I realize
that you are all busy dealing with a ton of other issues and tickets, and I
am grateful for all that you've done for us out here. But if the Michigan
GeoRef issue were successfully addressed, it would really provide a great
boost to open source software their enthusiasts in our state!
Thank you for your time, and keep up the good work!
Howard Yamaguchi
--
View this message in context:
http://osgeo-org.1803224.n2.nabble.com/Michigan-GeoRef-Michigan-Oblique-Mercator-EPSG-3078-tp6517423p6517423.html
Sent from the GDAL - Dev mailing list archive at Nabble.com.
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