Importing .DEM files to generate terrain

[IntelCoreDuo]

I'm using the latest SketchUp pro, and recently discovered the power of GIS. I've downloaded free high-res 0,25m accurate terrain data for Bergen, Norway (or anywhere else) but SketchUp will crash during the import, even when the file is tiny (small area, and .dem file is just a few kb)
At the moment I've managed to import the data by importing it to AutoCAD Civil 3D then converting to a surface, moving to 0,0, exploding to meshes and saving as .dwg.

Perhaps the coordinates are the problem, SketchUp will not accept my Autocad files unless I move them close to origo. Not sure how I can delete coordinates of a .dem file.

Any ideas?

[filibis]

@intelcoreduo said:

I've downloaded free high-res 0,25m accurate terrain data for Bergen, Norway (or anywhere else)

May i ask from where did you get/download that free high-res data? I can't seem to find anything higher then ~30m accuracy.

@intelcoreduo said:

but SketchUp will crash during the import, even when the file is tiny (small area, and .dem file is just a few kb)

I don't know why it crashes but if you could share the .dem , i can have a look.

[IntelCoreDuo]

@filibis said:

@intelcoreduo said:

I've downloaded free high-res 0,25m accurate terrain data for Bergen, Norway (or anywhere else)

May i ask from where did you get/download that free high-res data? I can't seem to find anything higher then ~30m accuracy.

@intelcoreduo said:

but SketchUp will crash during the import, even when the file is tiny (small area, and .dem file is just a few kb)

I don't know why it crashes but if you could share the .dem , i can have a look.

Sure, I use this website:
https://hoydedata.no/LaserInnsyn/
(Only covers Norway though) 0,25m accuracy in many cities and other areas. Let me know if you need help in getting the download settings right.

The DEM file is attached

---

dtm.rar

[filibis]

First of all i must say that i was fixing lots of DEM files that cause crash by converting them to UTC projection and save as ASCII dem files. However in your case this didn't work .

So after a lot of painful tests here is my short conclusion: There is something 'wrong' with UTM projections provided in that website. Here are my reasons:

1- Website provides DTMand DOMtype of DEM files. I'm not sure but this might be the core cause of problems.

2- Website doesn't let me get USGS DEM without UTM projection. If i can get a 'raw' dem (lat/long coordinate type), then i could just use my workflow mentioned above (which worked quite fine until now).

3- Although i can import their dem files to 3DEMand MicroDEM softwares without problem, it doesn't let me change UTM projection (This might not be an issue at all).

But the specifications of the files differs. Compare below 2 image.

4- I could get 'raw' GeoTIFF (without projection) but then 3DEM software gives this odd error when i try to save as ASCII dem file:

[IntelCoreDuo]

How strange! At least I am content that whatever was wrong isn't an easy fix, so I can put my mind at ease and to this the hard way through Civil 3D, then convert to .dwg and into SketchUp.
Thank you!

[Kristoffersch]

Hi,

I am having the same problem using USGS DEM files from høydedata. I have tried converting them to UTC projection and save as ASCII dem files in 3DEM, but get the same result as filibis. I have also tried converting GeoTIFF from høydedata with the same method. Have you found anyway around this problem besides using Civil 3D?