8 replies to this topic

[gregory]

Hi guys,
I try to get forest shapefile for Turkey. The first step was to try download landsat mosaic fo midlle east via geotorrent, unfortunelly with no lucky. My second try is to use gecover circa 2000 https://zulu.ssc.nasa.gov/mrsid/. To do a supervised classification first i have to mosaic the scenes and here comes to problem. I cannot merge mrsid file directly, and trying convert them to .img files i get uncompressed files about 5Gb each what doesnt make a sense beacouse of apllication speed. The software i can use for it is ArcGIS 9.2. Do you know any way to get out that?
thanks for replies
gregory

[macnetz]

Hi gregory,

I would try GlobalMapper and the ECW file format to do the task. You can mosaic the tiles using the AU-ECW-Compressor
http://www.advisory-...sor/AU_ECW.html

Regards - Anton

[gregory]

Thanks for the tip,
I had a look and the speciall license is necesarry to mosaic Mrsid files in ArcGIS. There is also another limitation The Mrsid compression tool that comes with ArcGIS has the limitation of file size that can be compresed (50MB). http://home.earthlin.....SA Photos.pdf
Anyway it looks like there is no other solution like to uncompress to tiff files then create mosaic and use your sugested software to compress this time to ecw.
Some already did and the continents mosaics are avilablle via geotorrent.org but the one for midlle east which is my AOI isn't available ( no ppl to share).

If anyone of you already downloaded that file and dont mind to share i would be really grateful
best regards
gregory

[macnetz]

he gregory,

which file do you need - there are 8 SID tiles covering turkey . . .

Regards - Anton

[gregory]

I need all 8 files which i already downloaded. The mosaic which i'm talking isn't avilable is Midlle East Landsat Mosaic in ecw format http://www.geotorren...ents/34.torrent. This file could safe a lot of time in my project but right there is no person who shares via torrent client.
grettings from poland
gregory

[macnetz]

hi gregory,

I don't have this file

btw: how do you plan to mosaic the whole Turkey?
You would have to reproject the SID files. The SID files uses UTM and Turkey covers 4 UTM zones (35 - 38).

Regards - Anton

[gregory]

Right now i'm resampling single bands from each 8 tiles to img files. Then i will merge them look for exact projection suit the best Turkey.
Thanks for you assist
gregory

[macnetz]

hi gregory,

maybe Richard can help you
http://www.geotorren...tails.php?id=34

This ECW file seems to fit perfect your needs.

Regards - Anton

[David T]

Another ArcGIS limitation to consider - I don't believe ArcGIS can handle a MrSID file larger than 2Gs. I could be wrong about that, though.

My SDE administrator and I was discussing MrSID tiles the other day. He is amazed that the last aerial flight of Camp Pendleton has a 4G MrSID file. He has been under the impression that about 2-3 gigs would be the limit.

We've not tried anything bigger than 4 gigs, but look into whether ArcGIS can handle something bigger than that.