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better sat image resolution

PostPosted: Tue May 10, 2016 4:51 pm
by Spookygnu
Is there a way I can use a 3072x3072 image as a sat map look much clear and more defined in detail in L3DT. At the moment I have this size in L3dt and I am using it with reference from google earth to edit my terrain in a live format. I'm lucky enough to have multiple monitor setup so I have this going on while I edit.

https://drive.google.com/file/d/0BwGVkyqKfsc0NEo4b2IzSW9DNmM/view?usp=sharing

Now as you can see i have a stripe across my image, which is rather annoying trying to edit my terrain. This crosses in various areas across the map. this is also a bit of an issue.

So, Can I have a better resolution map some how and how can I get rid of the stripe.

Re: better sat image resolution

PostPosted: Tue May 17, 2016 1:08 pm
by Aaron
Hi Spookygnu,

I apologise for this inconvenience, and for the delay in my reply. This is a known issue that occurs with particular ratios of heightfield and texture sizes. I should be able to write a script to re-pack the texture map mosaic to eliminate the streaking. What heightfield size were you using?

Best regards,
Aaron.

Re: better sat image resolution

PostPosted: Tue May 17, 2016 11:08 pm
by Spookygnu
thanks for responding to this thread Arron.

Atm I have this map set to 4096x4096 at 7.5 cell.

Is there a way to get a better resolution to the images aswell.

Re: better sat image resolution

PostPosted: Wed May 18, 2016 3:24 pm
by Aaron
Hi Spookygnu,

Okay, the streaking is happening here because the texture map is lower-resolution than the heightfield, which is quite unusual in L3DT. If you resize the texture to 4096x4096, the streaks will disappear. I should in theory be able to re-pack textures in Sapphire to support these unexpected sizes, but I'll have to think more about that.

As for the resolution; Sapphire will be displaying the texture at full resolution, so if it looks blurry, that's because the resolution of the texture is too low. From the numbers you've give, the size of a single texture pixel is 10 metres by 10 metres, or about the size of a modestly-sized house. Google Earth will have downloaded a much more detailed set of aerial images.

If you're after US data, you can use the USGS national map viewer to download 1m-resolution imagery:

http://viewer.nationalmap.gov/basic/

To cover the area you want, you'll need to download a set of images and stitch them together. Also, they're in jpeg2000 format, which L3DT doesn't yet support, so you'd first need to launder them through another program into a supported format. Lastly, the tiles you download from TNM won't necessarily align with the edges of your height data, so you'll need to do some appropriate cropping. Sounds a little finicky, but definitely possible.

Best regards,
Aaron.

Re: better sat image resolution

PostPosted: Wed May 18, 2016 5:29 pm
by Spookygnu
Thanks Arron,

I already have sat images downloaded at 2m res from TerraIncognita, they were then stitched/tiled together in Photoshop and aligned to fit with my heightmap. That was a right PITA. Got there in the end though.

I'll resize the images to 4096x4096 and see what happens.

cheers