"Tom Jackson" wrote in message
news
w6Dc.95742$2i5.90727@attbi_s52...
Try Oziexplorer (www.oziexporer.com,) and scanned FAA sectionals provided
by
Kyler Laird at aviationtoolbox.org.
The sectionals are "geo-tiffs" and Oziexplorer can import them and
automatically scale them to the proper lat/lon.
Have you actually done this? It didn't work for me-- the georeferencing nor
the image display. I posted to the Ozi-Users email list and got the
response below.
I would sure like to get it to work, so if you have some tips please let me
know at jclonts AT hot DOT rr DOT com.
Cheers,
John Clonts
Temple, Texas
Date: Sun, 20 Jun 2004 19:05:18 -0000
From: "rwcx183" xyzzy
Subject: GeoTiff support?
John,
There's more than 1 problem with what you're trying to do. Firstly,
the Geotiff tags for this image specify that the image is in Lambert
Conformal Conic projection and Ozi cannot (to my knowledge) handle
that projection on import. You can try to use Albers (equal area) as
an alternative, since it has the same set of required parameters.
That sometimes results in acceptable accuracy, but sometimes not
(this case). You can also manually calibrate the map image using the
just the upper left and lower right corners as cal points. You will
have to convert the lambert grid coordinates for the corners to
lat/lon or UTM first though, since Ozi doesn't allow specifying
coordinates in Lambert grid. That Ozi does not support Lambert
Conformal Conic projection on import, is the most glaring omission,
in an otherwise very capable program. That and the non-support of
any linear unit besides meters, for georef coordinates. Here's the
Geotiff dump of the georeferencing info for your image:
Geotiff_Information:
Version: 1
Key_Revision: 1.0
Tagged_Information:
ModelTiepointTag (2,3):
0 0 0
250233 -715515 0
ModelPixelScaleTag (1,3):
128 128 0
End_Of_Tags.
Keyed_Information:
GTModelTypeGeoKey (Short,1): ModelTypeProjected
GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
GTCitationGeoKey (Ascii,8): "unnamed"
GeographicTypeGeoKey (Short,1): GCS_NAD83
ProjectedCSTypeGeoKey (Short,1): User-Defined
ProjectionGeoKey (Short,1): User-Defined
ProjCoordTransGeoKey (Short,1): CT_LambertConfConic_2SP
ProjLinearUnitsGeoKey (Short,1): Linear_Meter
ProjStdParallel1GeoKey (Double,1): 38.6666667
ProjStdParallel2GeoKey (Double,1): 33.3333333
ProjFalseEastingGeoKey (Double,1): 0
ProjFalseNorthingGeoKey (Double,1): 0
ProjFalseOriginLongGeoKey (Double,1): -100.583333
ProjFalseOriginLatGeoKey (Double,1): 38
End_Of_Keys.
End_Of_Geotiff.
Projection Method: CT_LambertConfConic_2SP
ProjFalseOriginLatGeoKey: 38.000000 ( 38d 0' 0.00"N)
ProjFalseOriginLongGeoKey: -100.583333 (100d35' 0.00"W)
ProjStdParallel1GeoKey: 38.666667 ( 38d40' 0.00"N)
ProjStdParallel2GeoKey: 33.333333 ( 33d20' 0.00"N)
ProjFalseEastingGeoKey: 0.000000 m
ProjFalseNorthingGeoKey: 0.000000 m
GCS: 4269/NAD83
Datum: 6269/North American Datum 1983
Ellipsoid: 7019/GRS 1980 (6378137.00,6356752.31)
Prime Meridian: 8901/Greenwich (0.000000/ 0d 0' 0.00"E)
Projection Linear Units: 9001/metre (1.000000m)
Corner Coordinates:
Upper Left ( 250233.000,-715515.000)
Lower Left ( 250233.000,-792315.000)
Upper Right ( 352633.000,-715515.000)
Lower Right ( 352633.000,-792315.000)
Center ( 301433.000,-753915.000)
Now, to the obvious problem that you're seeing. I ran the image
through a tiffinfo utility and discovered the problem. Here's what
tiffinfo shows:
TIFF Directory at offset 0x15ff3e
Image Width: 800 Image Length: 600
Bits/Sample: 8
Sample Format: unsigned integer
Compression Scheme: None
Photometric Interpretation: RGB color
Samples/Pixel: 3
Rows/Strip: 10
Planar Configuration: separate image planes
Tag 33550: 128.000000,128.000000,0.000000