Hi Greg,
To be honest, when I get a very large image file I want to display, I
use GDAL to create image tiles out of it (Like Google
Tiles/OpenStreetMap tiles) and then use the MapTileLayer to display
it. GDAL will merge files to let you create a large area tile set,
too. GDAL has a command line script that you point at an image (or
set of images) and tell it where to put the tiles, and you're done.
If you use GDAL to create tile sets, you have to set the MapTileLayer
with a com.bbn.openmap.dataAccess.mapTile.TMSMapTileCoordinateTransform
so it knows how the tiles are laid out (the y tile coords are opposite
of OSM tiles).
The MapTileLayer takes properties about the tile set so it knows how
to display it. You can keep the properties in a tiles.omp file
underneath the tile set root directory, or set the properties on the
layer itself. The javadocs for MapTileLayer have more information.
JAI is probably the best bet when handling images of this size, but as
you've noted, it doesn't really handle really large images very well.
- Don
On Mon, Jun 18, 2012 at 7:29 PM, Greg Jewell <greg17_at_jewell.net> wrote:
> Hello,
>
> Has anybody had any experience trying to get OpenMap to load very large
> GeoTIFF files? I am able to display an image that is about 35MB in
> size, but it takes a significantly long time to load. (Our normal
> environment doesn't utilize JAI native libraries, but even with the
> libraries it's still pretty slow.)
>
> We were recently given several files that range in size from 700MB to
> 3.3 GB. With the maximum VM heap size set to 1GB, I get our of memory
> errors even on the 700MB file. Setting it higher will prevent the out
> of memory errors, but the imagery doesn't display. Changing the tile
> cache size hasn't had any apparent effect, either.
>
> My environment is Windows XP 32 bit, Windows 7 64 bit (with the 32 bit
> JVM), and OpenMap 4.6.5. Does OpenMap 5 use something other than JAI to
> process GeoTIFF images? JAI development is dead, I'm afraid, and it
> seems to really struggle with larger images.
>
> As far as I am aware, the imagery is valid and uncorrupted -- PhotoShop
> loads it "just fine".
>
>
> Thanks,
> Greg Jewell
>
> --
> [To unsubscribe to this list send an email to "majdart_at_bbn.com"
> with the following text in the BODY of the message "unsubscribe openmap-users"]
--
[To unsubscribe to this list send an email to "majdart_at_bbn.com"
with the following text in the BODY of the message "unsubscribe openmap-users"]
Received on Mon Jun 18 2012 - 21:43:45 EDT