UTM projection of elevation data is good for removing distortion, and I also use it because it's good for combining terrains of different sizes.
As mentioned in another post I was trying to include Oshyan's 3m Mt St Helens terrain into my terrain set of the same area. As they both used UTM projection it should have fitted in quite nicely. To line them up I resized Oshyan's huge terrain down a bit in TG0.9, converted it to a TIFF with TerraConv and finished the resizing/alignment with one of my GEOTIFFs in Photoshop.... measured the offset of the centres of the terrain, plugged it into my terrain set data spreadsheet to give me the theoretical offset from the centre of my terrain set.
As there are narrow strips of 0m altitude along the sides of this TER I set the mask width to remove these.
So far so good....
[attachimg=#1]
Haven't looked really closely along the entire edge but it looks pretty good to me so far.
Here's a preview link to the donwload directory where my terrain set will live:
http://www.path.unimelb.edu.au/~bernardk/terragen/terrains/US_3peaks/files/ (http://www.path.unimelb.edu.au/~bernardk/terragen/terrains/US_3peaks/files/)
Canopy and land cover maps are on the way.
Getting ready to go to work so i don't have time to find a link to Oshyan's terrain... Thanks for the terrain Oshyan, and hopefully you'll find this useful as well.
Wow. Cool. :o
Another test on this terrain set....
Well you've heard me rant about canopy and landcover maps.. and I've posted samples of tree distribution using the canopy map. The landcover map is not immediately useful but it does contain some very useful data (if only low res). What you do with it is limited only by your imagination. Here's the result of my morning train ride ;)
I selected the two main colours from the map that represent concrete/pavement and constructed a mask to simulate artificial lights (cities and highways). Quick and crude... but interesting all the same. Apart from tweaking the colour/luminosity, I'd also increase the contrast in the mask (only two colours, but separating them more would make it look more realistic) add a noise function to the mask to break it up a bit more. You could also add some extra glow by creating a second luminous layer with less luminosity using a scaled down version of the mask image. Anti-aliasing should blur the edges enough to create the soft spread.
As a hack I think it works quite well and it's easier to set up for elevation data than the global city lights image (and possibly higher res?).
The view is from the NW corner of the 410km terrain looking back towards Rainier etc...
(canopy and landcover masks are now added to the url above... I'll set up a proper page tonight with the extra info)
Ben, you may find this data interesting/useful in rounding out your sets of data:
Canadian DEM data 0.3 - 0.7 arc seconds:
(the British Columbia data in particular is excellent)
http://www.geobase.ca/geobase/en/browse.do?produit=cded1&decoupage=50k (http://www.geobase.ca/geobase/en/browse.do?produit=cded1&decoupage=50k)
Canadian Vector Data (CanVec or NTDB - National Topographic Database layers)
Includes Vegetation, marsh, snow layers etc, to mask surfaces:
CanVec:
http://ftp2.cits.rncan.gc.ca/pub/canvec/ (http://ftp2.cits.rncan.gc.ca/pub/canvec/)
NTDB:
http://ftp2.cits.rncan.gc.ca/pub/bndt/ (http://ftp2.cits.rncan.gc.ca/pub/bndt/)
Raster Topographic Maps at 1:50,000 and 1:250,000 (300 DPI Geotiff Format)
http://ftp2.cits.rncan.gc.ca/pub/canmatrix/ (http://ftp2.cits.rncan.gc.ca/pub/canmatrix/)
And of course the index maps so that the file names/numbers for everything above makes sense:
ftp://ftp.nrcan.gc.ca/ess/topo/NTSindex/ (http://ftp://ftp.nrcan.gc.ca/ess/topo/NTSindex/)
I spend most days working with this junk, so if there are any other layers that you would find helpful for masking, let me know and I am sure I can find them or at least know the right person to ask for them.
-Ryan Archer
Many thanks Ryan
These are very useful. ;D
I'm no expert when it comes to working with terrain sets but I thought this would be a useful to the folks here.
http://www.usna.edu/Users/oceano/pguth/website/microdem.htm (http://www.usna.edu/Users/oceano/pguth/website/microdem.htm)
I have just touched the surface of this software (used it more with Terragen 0.9) and it might be worth exploring...
Glen
Thanks Glen. It might be useful for people stuck with only 3DEM. I use GlobalMapper (v4) to combine data and export as Geotiff for conversion to TER with 3DEM (v4 of GM only exports TERs up to 2049x2049).
Here's a reverse view of the previous render.... not much point having a high res terrain unless you put the camera near it ;) From the rim of St Helens the lights of Seattle can just be seen on the horizon.
This is brilliant. I love how you think. Good job, Ben.