Convert ascii to DEM
JSL
Global Mapper UserTrusted User
Hi, I'm trying to import a large xyz file from this site: http://geomag.org/models/wdmam.html in order to create a DEM that looks like the image at the top of the webpage:

I have no experience in this, however, and these are huge files--when I downloaded the fourth file down on the list, the zipped xyz file, it translated to over 25 million points. I tried to batch convert it to a USGS DEM file, but it failed to create anything.
Any help would be appreciated...

I have no experience in this, however, and these are huge files--when I downloaded the fourth file down on the list, the zipped xyz file, it translated to over 25 million points. I tried to batch convert it to a USGS DEM file, but it failed to create anything.
Any help would be appreciated...
Best Answer
-
You can open ascii files, either zipped or unzipped. but the data must be in either X, Y, Z or Y, X, Z format.
- Go to file "open generic acsii text file"
- Select your file. OK, and tick "elevation grid from 3D point data"
- Also select Y or Y as first coordinate
- Make sure that the box "treat 3rd coordinate as elevation" is ticked
- Hit OK and select tight or loose distance criteria (suggest trying to see which gives you the best result)
- Select projection
- That's it
I hope that this helps.
Cheers
Answers
-
Thanks, that worked beautifully!
Howdy, Stranger!
Categories
- 12.2K All Categories
- 5.3K Features Discussion
- 312 Downloading Imagery
- 1.2K Elevation Data
- 371 Georeferencing Imagery Discussion
- 580 GM Script Language
- 42 User Scripts
- 111 GPS Features
- 388 Projection Questions
- 788 Raster Data
- 1.3K Vector Data
- 6.4K Support
- 159 Announcement and News
- 881 Bug Report
- 554 SDK
- 1.1K Suggestion Box
- 3.6K Technical Support
- 520 Other Discussion
- 125 GIS Data Sources
- 26 Global Mapper Showcase
- 217 How I use Global Mapper
- 99 Global Mapper Forum Website