Olaf
>what about experiences with transfer of raster maps between Microstation
and MapInfo.
>...at the end I have only the linework transferred and not a raster
background map. Our client uses IRAS/C and/or /B for raster registration and
told me that they observed displacements even if they try to open these
raster maps in standard MicroStation!
Were your MI images registered in another software package and then
translated to MapInfo?
If not, I would advise against registering images (with distortion ie
unrectified scanned aerial photography) in MI and then translating these to
IRAS/C. The reason being that MI doesn't warp/rubber sheet the image to fit
the vectors, after 'registration' MI stretches /rotates /skew's the vectors
of overlain tables to give the illusion that the image is in the correct
position. Close the image layer and the vectors are back to normal.
IRAS/C to MapInfo
We do our image registration in IRAS/C and then translate the registered
imagery to MapInfo. One of our programmers wrote a pearl script that reads
the header information out of the IRAS/C .itm file and reformats this into a
.tab and accompanying .tif for MapInfo.
>I asked for possible options to export/import the raster as GeoTiff or with
an .tfw file (what could be read into >MapInfo), but they didn't know about
such an option in MicroStation.
MapInfo to IRAS/C
I've clipped a part of the E:\WIN32APP\ingr\IRASC\readme.txt file:
A "world file" is an ASCII file containing a set of affine transformation
coefficients which map from raster to world coordinates:
x' = A * column + B * row + C
y' = D * column + E * row + F
written in the order ADBECF. The "world file" does not contain any infor-
mation on coordinate system or units. The name convention for "world files"
is a file of the same name as the image, with an extention formed from the
1st and 3rd characters of the extension of the image file, with a "w"
appended:
xxx.tif -> xxx.tfw
xxx.bip -> xxx.bpw
xxx.jpg -> xxx.jgw
xxx.sid -> xxx.sdw
If there is no matrix in header, or the matrix is null (all 0s) or identity
(1s on the diagonal, and 0s elsewhere), then I/RAS C will look for a
"world file", and use it to place the image in the design file.
Note: translators for ESRI .tif/.tfw file pairs, ERDAS .lan,
and ESRI .bil/.bip files are available on the Intergraph web page,
under Mapping/GIS, Free. A utility to create a .tfw file from a
map-registered image is also available by contacting Customer Support.
This is basically describing the format of a "world file" that IRAS/C 7 can
read.
An example of one of mine is below (coords in New Zealand Map Grid):
20.0
0.0
0.0
-20.0
2810010.0
6249990.0
So if you know the specs of your .tif image you can format them (as above)
in a text editor and save with a .tfw extension. Then open in IRAS/C version
7.
Best of luck
See ya later
Kia kite ano
Scott
Scott Lillas
GIS Specialist
Environment B.O.P
P.O. Box 364
Whakatane
Phone 07 307 2545
Fax 07 307 2544
Email [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
Web site www.boprc.govt.nz <http://www.boprc.govt.nz>
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