Tom, MI 4.1 does open *.bil image files, however, if the *.hdr file that should
come with it is not correct, it will not open. You may have to either make a
new one, or modify an existing one to get it to open correctly. Hopefully you
were given the complete set of descriptive data that typically comes with this
image file.
Regards,
-Bill
This should hopefully assist you.
Question: When opening a *.bil file in MapInfo, an error message is received,
"Raster Engine unable to recognize Image format when attempting to open .bil
image."
Answer:
When opening .BIL images, the image needs to have a valid header (*.hdr file)
which contains specific image information related to the .BIL file needed for
MapInfo's raster engine to open it.
The .hdr file contents need to look like this:
NCOLS e.g.: 6400 number of columns in image
NROWS e.g.: 4800 number of rows in image
NBANDS e.g.:1 number of bands in image
NBITS e.g.: 8 number of bits per pixel
BAND_RGB *** e.g.:1 1 1 RGB value of bands in image
BANDROWBYTES *
TOTALROWBYTES *
*Refer to Q007 below (Excerpts from Raster FAQ.txt and sample attached below)
***Refer to Q008 below
SPOT and most other .BIL format images should have an included .hdr file that is
shipped with them.
They may also have *.blw, *.rep, and *.txt files containing image related
information which must be deciphered
to put into the header file and later to register the raster image once opened.
A *.BLW file may have information like the following in it that contain image
dimensions in meters from
Min X, Min Y to Max X, Max Y. *.REP files should be very similar to *.hdr
files.
1.00000000000000
0.00000000000000
0.00000000000000
-1.00000000000000
590700.00000000000000
3264000.00000000000000
A *.Txt file for registration info might look like this:
PROJECT: GUADALUPE COUNTY, TEXAS DOQQ 05/06/96
QUADRANGLE: NEW BERLIN 29098D1 NE 3'75" QUARTER QUAD
QUARTER QUADRANGLE CORNERS: METERS
CORNER LONG LAT EAST NORTH SAMPLE LINE
===============================================================
NE -98 00 00 29 30 00 596902 3263825 6202 175
NW -98 03 45 29 30 00 590844 3263775 144 225
SW -98 03 45 29 26 15 590900 3256850 200 7150
SE -98 00 00 29 26 15 596962 3256900 6262 7100
===============================================================
DATUM: NAD83
UTM ZONE: 13
IMAGE: MONOCHROME
EASTING AND NORTHING OF (1,1) 590700 3264000
PIXEL SIZE: 1.00 METERS
Once the correct Header (.hdr) file is created, the image can be opened open it
via File>Open Table>Raster
Image and begin the registration process.
Set the PROJECTION to be used on the image Control Points and the UNITS used in
the projection then using
the information from the *.TXT file above, create control points with the image
and map information given.
***Make sure the Projection information MapInfo has in its mapinfow.prj file is
the same as what is used above
(i.e.: Easting and Northing differences)
e.g.: (for this Image)
Pt 1 (the NW point)
Map X: 590844 ( the East column from the .txt file)
Map Y: 3263775 (the North column from the .txt file)
Image X: 144 (The Sample column from the .txt file, which corresponds to
the image column)
Image Y: 225 (The Line column from the .txt file, which corresponds to
the image row)
Excerpt from Raster FAQ:
Q007: My SPOT image won't load, why?
Q007: Why do I get "Invalid Raster Format" whenever I attempt to load a
SPOT file?
A007: "SPOT files" are actually sets of files. Typically, there are three
files in a set. The (required) BIL file is the raster data itself. The
(required) HDR file holds the description of the file: it's length and
width, etc. The third file (not required) is a STX or CLR file. This
file is used to map colors to the raster data. If it doesn't exist, then
the image will be considered grayscale. (Of course, if it is actually
a color image, it will looks wrong-- there is no way to fix it.)
SPOT images all come with these pieces. If they aren't there, then
someone lost or deleted them.
The following tags are used from the HDR file. They are case insensitive.
These are required:
NCOLS
NROWS
NBANDS
NBITS
BAND_RGB
These are optional, but used if present:
SKIPBYTES
RECORDSKIPBYTES
BANDROWBYTES
TOTALROWBYTES
Q008: I have a SPOT BIL file but no HDR, what do I do?
A008: You're in trouble. Without the length and width of the image, it is
probably hopeless. If you have the length and width, then make a HDR
file with NCOLS equal to the width and NROWS equal to the length. You
now need to guess what the rest of the required values are.
If you think the image is 8-bit, you can try:
NBANDS 1
NBITS 8
BAND_RGB 1 1 1
If you think the image is 24-bit, or the above doesn't work, you can
try:
NBANDS 3
NBITS 8
BAND_RGB 1 2 3
If it looks like an image, but has the wrong colors, try:
NBANDS 3
NBITS 8
BAND_RGB 3 2 1
If none of those settings work, there's still one more thing they can
try. Some SPOT images have extra information at the beginning of the
file which needs to be skipped. There are two ways to figure out how
much to skip. The first is to figure out what (NROWS*NCOLS*NBITS/8) is
for the image. If it is smaller than the actual length of the file
in bytes, then subtract it from the actual length. Put this value in
the HDR like this:
SKIPBYTES number_of_bytes
If this method doesn't work, the last resort is to examine the file and
try to guess where the data begins. Not an easy task, but a last
resort nonetheless.
If the image still doesn't load, then you really have no chance of
making it work. Call SPOT and get a replacement file set for the
pieces you lost.
See A007 for a list of the required and optional tags.
(See attached file: RasterFAQ.txt)
Mail List:owner-mapinfo-l
From: Tom Brockenbrough <[EMAIL PROTECTED]> on
06/16/99 06:46 PM GMT
To: [EMAIL PROTECTED]
cc:
Subject: MI .BIL files
Hello All:
I have some aerial imagery with a .BIL extension. Does anyone know in
what software I can open this image? Have had no luck in MapInfo 4.1 or
the few image software formats (Paintshop Pro, etc.) I have available.
Thanks in advance
Tom Brockenbrough
Accomack County, VA
Dept. of Building, Planning, & Zoning
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