OziExplorer .MAP file should be useable with all file formats, not only GIF

[jcrepetto]

OziExplorer can read many standard and proprietary file formats : TIFF, BMP, JPG, PNG, BSB, BSB 4, BSB 5, ECW, MrSID, OZF2, OZFX3, Maptech Terrain Navigator maps (.024,.100,.250) and Maptech Aeronautical charts (.AER), RIK, Kompass

Not all of these formats are supported by GDAL, but it should be possible to use .MAP files with other formats than GIF.

[Even Rouault]

Quoting Frank on ​http://lists.osgeo.org/pipermail/gdal-dev/2010-January/023328.html :

Jean-Claude,

I see that there is a GDALReadOziMapFile() function that could be
utilized in other drivers too.  I presume in 1.7 Andrey implemented
use of it in the GIF driver because that is where he needed it.

I'm hesitant to spread all the possible supporting information formats
(.aux, world files, ozi map files, mapinfo files) in all drivers.  One
reason is the amount of code involved, which we could reduce by some
more generic mechanism to lookup supporting information.  The other reason
is that probing for so many supporting files may have noticable effects
on performance in some cases.

I am however open to improvements in consistency and approach if there is
broad support.

[dron]

Replying to rouault:

I see that there is a GDALReadOziMapFile() function that could be

utilized in other drivers too. I presume in 1.7 Andrey implemented use of it in the GIF driver because that is where he needed it.

That is true. I needed it for GIF files, also I've seen its usage with JPEG and BMP files, so these ones could be added first.

I am agree that some consistency is needed in this area. In first of all we need to secure an order of external georeferencing lookup to ensure that all drivers will read external files in the same way. What about adding the special function GDALReadExternalGeoref() which in turn will call functions to read world files, mapinfo and ozi files? Individual drivers will call that function instead of sequence of GDALReadWorldFile(), GDALReadTabFile() etc. That function can take the list of possible external georeferencing file formats to search, so we can avoid reading everything if we don't want to. Something like:

GDALReadExternalGeoref(int nGeoFormats)

where nGeoFormats is a combination of flags
READ_ALL --- try all possible external formats,
READ_WORLD --- read world file only,
READ_MAPINFO_TAB --- read Mapinfo .TAB file only,
READ_OZI --- read Ozi Explorer .MAP file.

Performance issue remains though.

[vadp]

Replying to jcrepetto:

it should be possible to use .MAP files with other formats than GIF.

I think there is another way of getting this functionality. You may think of .MAP file as another virtual format, something like .VRT. It contains a link to an image file, projection, datum, so why not.

I've made a sample script for converting .MAP into .VRT. Perhaps someone would be interested to have a look, so I'll attach it here.

BTW: It seems there is a bug with a current implementation of .MAP projections. At least for Mercator it produces +k=0 by default, then the PROJ is not happy about it.

[hamish]

Hi,

with python 2.4.4 I get this error from ozi2vtr.py:

  File "./ozi2vrt.py", line 30
    return out[0] if out else default
                   ^
SyntaxError: invalid syntax

?

thanks, Hamish

[vadp]

Replying to hamish:

Hi,

with python 2.4.4 I get this error from ozi2vtr.py:

  File "./ozi2vrt.py", line 30
    return out[0] if out else default
                   ^
SyntaxError: invalid syntax

Hi! That was fine with python 2.6.4, but hdr_subparm() were not needed at all as it was mere leftover from my kap2vrt.py script. I'll upload a "trimmed" version

[vadp]

a script to convert .MAP file into .VRT

[vadp]

Hello, I'm posting a newer version of my ozi reader script. It supports more projections/datums, so have a look if interested.

[vadp]

an enhanced version of the script to convert .MAP file into .VRT

[vadp]

for ones interested in, the latest version of the ozi2gdal.py can be found here ​http://talk.maemo.org/showthread.php?t=57469

[jcrepetto]

OziExplorer .MAP driver

[jcrepetto]

To fix this ticket, I am submitting a new driver for OziExplorer .MAP files. With this driver, every image file format supported by GDAL will be supported in .map files. It won't be necessary to add a new autotest script, because the current OZI driver test will test both OZF2 files and MAP files.

[Even Rouault]

Committed in r25287 (with a few minor fixes). Thanks