Author Topic: Imported DEM in the wrong Place  (Read 279 times)

Offline cyphyr

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Imported DEM in the wrong Place
« on: July 06, 2017, 08:59:08 PM »
I am importing a set of GeoTiffs that represent Papua and Papua New Guinea and they are loading in the wrong place.
Instead of loading just on and just south of the equator they are loading close to the south pole and rotated through 90 degrees.

The files are from a reliable source: http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp

I'm at a bit of a loss what to do to fix this, since I can't see any way to rotate the GeoTiff's and moving the planet makes no change either.

Suggestions warmly accepted :)
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Offline Oshyan

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Re: Imported DEM in the wrong Place
« Reply #1 on: July 06, 2017, 11:42:50 PM »
Turn off auto-georeference and set the georeferencing manually. The correct georef data seems to be on the download page once data is selected. Also it appears to just be bog standard SRTM data so you could try an alternate source, it's widely available.

- Oshyan

Offline cyphyr

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Re: Imported DEM in the wrong Place
« Reply #2 on: July 07, 2017, 09:23:45 AM »
Hmm still not working propperly. I can see the numbers showing the extent of the North/south Lat/Long and they look about right, in this instance a square 5 to 10 degrees south of the equator but the placement on the globe is way off that weather I type in the numbers manually or not.

You can see from the screen cap that the tile is importing way off the equator whereas the numbers indicate it should be between -5 and -10 9 (or 5south and 10 south).

I have opened the tiles in Global mapper and matched their positions with photo data but it's only once I try to get the data into Terragen that it goes wrong.

The GeogImage shader lined up perfectly with the imported dem so that is in the wrong place too.

Pretty sure I'm missing something pretty basic here but I've never had to work with real world data before. It's so much easier when you can do it all procedurally !!
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Offline bigben

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Re: Imported DEM in the wrong Place
« Reply #3 on: July 09, 2017, 03:51:47 PM »
Popped back after upgrading to GLobalMapper18 and TG4 and what's at the top of the list  ;)

Is there any reason you want it in the actual location or do you want it up near the origin? I normally set the coords for the planet apex to the centre of my DEM(s) which makes camera placement a lot easier.

PS. Check out https://github.com/openterrain/openterrain/wiki/Terrain-Data for some newer sources of data.  SRTM30m will get you a much nicer terrain, and SRTM15plus has a good compilation of bathymetry
« Last Edit: July 09, 2017, 04:15:57 PM by bigben »

Offline cyphyr

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Re: Imported DEM in the wrong Place
« Reply #4 on: July 09, 2017, 05:09:41 PM »
Hey Ben, good to see you again.
Well eventually where ever the camera lands up will be at the planet apex but for the time being I'd just like to get the imported srtm files to land where they should on a globe.
It's going to be a lot easier planning camera moves across diferent studios if data is comming in where we expect it to.
Papua New Guinea in my sample in on and just south of the equator. The Terragen coordinates (as shown in the dialoge node window) agree with this however that is not where it is ending up. It's saying one thing and doing another. Baffeling ..!
I'm using SRTM30 for closer shots and the SRTM 90 for wider earlier shots and the NASA Blue Marble stuff for global level stuff (all heavily edited of course)
:)
cheers

EDIT: Your clue about moving the coordinates to the apex did the trick. Setting the apex as 90 0 puts Papua New Ginea and Borneo in the right place. Thankyou
« Last Edit: July 09, 2017, 05:41:18 PM by cyphyr »
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Offline bigben

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Re: Imported DEM in the wrong Place
« Reply #5 on: July 09, 2017, 11:00:20 PM »
Yes, 0,0 at the apex gets very confusing when you're trying to navigate around the entire globe. I'm updating my global dataset for a visualisation workshop coming up in a few weeks. Give me a yell if you need something.