Thought I would share my advice, but I`m sure you might be aware most of them:
1. Use a
Map Catalogue containing all the images
I've tried that per Mike's suggestion in a previous post. That did save some, but it still is not enough to kick out these large datasets.
2. When exporting to ECW it will create an image as large as the
bounding box of all the images - so try to see if the bounding box is very large. Remeber ECW will also try to "compress" all lines outside your actual images inside the bounding box. You can get a very large bounding box in atleast two cases:
2A: for instance if you have
two areas far away from each other.
2B: If one or more images are
incorrectly georeferenced (meaning one image will end up in coordinatespace 0,0 while the rest will be at the correct place - thus creating a bounding box from 0,0 to 500000, 500000 or whatever your coordinates are)
Bounding Box is not an issue. Most of the counties are fairly "square" so there is not a lot of "empty" space in the bounding coordinates. All files are in proper coordinate systems.
3. GlobalMapper for the moment only use
one core for processing, ER Mapper which costs more money will use all available processors decreasing the time
4.
Networks are unstable - so my advice is to have the files available locally or on a USB/firewire disk so they are always available - I have experienced conversion stopping after 2 days just because the network was down for 1 sec - NEVER again !
LOL! I feel ya there. I learned very quickly to work locally. I've been running these locally.
5. ECW files generate
temp-files in the same catalogue as the output - so I suggest the output file to be on a local or USB/firewire (not the same as the input files) for fastest times
6. Multiple instances running once. I have experienced problems running two instances of GlobalMapper on the SAME dataset but I guess you are running each instance of GlobalMapper on completely different files? (ie no overlapping etc..).
I've only run one instance of GM at a time. I fear this tower of mine would really choke if I tried to run any more than one.
7. Turn off
anti-aliasing/fill small gaps to speed up processing.
I'll try that!, Thanks.
8. Perhaps you can try a
test with smaller resolution first, for instance 50m, just to see if it manages to create "something" and that there is nothing wrong with the input files?
That is almost what I'm doing now. See below. I've also been running older imagery that we have with no problems. Its only 10" pixel resolution and has half to maybe even a quarter of the tiles. Those go well.
9. Running multiple instances eat RAM - remember the limitation on Win 32 bit and your
2GB of RAM. Try to start only one instance of GlobalMapper and do one county and if it "hangs" for a long time , check the amount of
used RAM and the
Windows SWAP file to see if it is swapping to disk all the time or not.
Sorry for the long reply, however I did not have time to shorten it
Let us know how it goes.
GlobalMapper: Will the new v11 be able to use more than 4GB ram and more CPUs when creating ECWs or is the number of CPUs a limitation on the ECW-dll itself?