[Gdal-dev] Suggestion about project on Pocket PC

[Frank Warmerdam]

On 11/22/05, Alper Dinçer <alperd at ce.metu.edu.tr> wrote:
> I am a new member, I have a master thesis about showing satellite images
> with road index on pocket pc with local data.
>
> I choose the .Net compact Framework (CF) platform with C#. I have started
> the project 2 months ago, but I still don't have idea about how to do the
> project. Let me explaing the gaps of my project. The satellite images are
> approximately 2 – 10 MB JPEGs. The problem is image size are too big for
> pocket PCs.
>
> First I thought about tiling the image like google maps or Ka-map, but it is
> very hard to implement on .NET CF without using a mapping server.
>
> Then I searched for reading some part of images, I found JPEG2000 has a
> property of Region of Interest (ROI), but I didn't find a library or API for
> .NET CF.
>
> Now let me ask my questions :
>
> 1-       Which type of image (TIFF, JPEG vs) you are suggesting to use in
> project?

Alper,

It will depend on a variety of factors, but I would think that
using JPEG, but pre-processed into appropriate sized chunks
(and possible with overview layers) would be the easiest approach.
I am assuming you can preprocess your data off the pocket pc,
and then distribute the "optimized" imagery to handheld.

> 2-       Is there any image type that we can read the interested part
> without loading it to the memory?

Various uncompressed formats will support this.  You can also
do this with formats like ECW, JPEG2000 and MrSID as long
as you can get libraries for your platform that support the formats.
The significant advantage of ECW/JP2/SID for your situtation would
be better compression for a desired quality level.

> 3-       Is there anybody porting GDAL to .NET CF?

There is an effort underway to build selected parts of GDAL
under WinCE *and* there is an effort to provide .net bindings
to GDAL that would hopefully port.  However, if you need is just
to display preprocessed RGB images I think GDAL would be
overkill (and perhaps pretty heavy for platform).

Note, the GDAL tools might be very helpful for processing
your images into tiles and overviews on a desktop or server
system before distributing to the pocket pc.

Best regards,
--
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent