aster global dem tiff

Hi! I just started evaluating world machine yesterday and i wanted to import some DEM data that i got from this page: http://gdex.cr.usgs.gov/gdex/

What i get is a tiff image which represents some sort of a heightmap. This is a tiff file that i received for one part of the world:
https://dl.dropbox.com/u/79625595/world%20machine/20121031163109_819332427.tif

When i load the tiff into the world machine i get a terrain without any elevations. Do you have any good resources or pointers how to get a correct terrrain from these types of images?

This is what i get, some texture on the surface but no elevations:
https://dl.dropbox.com/u/79625595/world%20machine/tiff_problem.png

Hi mpupovac, just imported the tif you posted no problem. Make sure you have the device import NOT set to interpret as RGB. Also you might try changing the device import height range from natural file elevations to something else. The terrain is probably quite flat. Also I always set Set Terrain Color on the left of the main view to acid bleached world-gives the best view of details.
The terrain does look a bit screwy though in the lower half of the file. Could be invalid data in the satellite imagery, or it could be an area where there is no data, like sea, or large lake. Set your height range quite high and you’ll see what I mean. I’m not using the beta here, this is 2.2. //just checked this and I think it’s because the WM world extents are not set to rectangular…hmm, nope, setting to non square extents and 1 px = 1 km doesn’t solve it. It opens in Global Mapper without any of the problems.

monks

Hi!

Thanks you for your answer. Eventually i managed to get it imported. But now i have an export problem, and perhaps someone knows what i’m doing wrong. The game engine i am using (heroengine) supports r16 and r32 import pipeline. They claim there is nothing wrong on their side, but when i import two neighbouring heightmaps i see the asimetric vertical gap.

a. (image 1) shows that there is no missing data between the left(western) and right (eastern) heightmaps.
b. (image 2) shows that there indeed is an asimetric vertical gap between these two tiles


image1


image2

Can anyone please help me?

It looks like your vertical scale is off between the two files…

A few checklist questions:

  1. Is altitude scaling set to Natural (file) elevations or Specified Range? (Full range will cause scaling differences)

  2. Are you using a Clamp with normalize input, an equalizer device, or anything else that in the device workview has a red ! mark next to its name?

These are the common culprits for height scale differences.

Hi!

  1. altitude is set to Full Range. If i try using natural file elevations i get a flat heightmap. Should i try something else?

  2. im just using the file input and height output devices. nothing more.

keep it set to natural file elevations, then add a clamp device after the file input device. Adjust the range in the clamp device to bring your terrain up to the level you want!

So, i should use the clamp device, but without the normalize output checked?

yup. just manually adjust the sliders to make the terrain take up the vertical range you want

Well, it happened to be a bug in the game engine import pipeline, which is now fixed, so i can import data with no problems.

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