Messed up dem hightmap?

[Servo]

I just downloaded the one hightmap from the edc.usgs.gov web site for Canada. But it seems to be messed up and it was not because of anything I’m doing that messed it up, I tried it on two different computers and it was still messed up when opening the dem file in VTbuilder on both computers. all other dems load up ok.

Can someone else try this dem file out
http://edc.usgs.gov/products/elevation/gtopo30/w140n90.html
And let me know if they also are having problems with it, if they are I need to contact the web site and let them know the file is messed up.

[Aaron]

Hi Servo,

Might I ask you to be more precise about what you mean by the term "messed up?". Can VTBuilder read the file, or does it throw an error? Are the contents obviously corrupted in some way? If yes, how? Have you looked at the VTBuilder error log? It's located at:

XP:

Code: Select all

C:\Program Files\VTP\Apps\Debug.txt


Vista:

Code: Select all

C:\Users\[username]\AppData\Local\VirtualStore\Program Files\VTP\Apps\Debug.txt


In any case, I'm neither a DEM expert nor an expert with VTBuilder, but I do know where you can find both: the Mailing list of the Virtual Terrain Project. If there's a problem with the DEM, the list members will be able to find out what it is, and if there's a problem with VTBuilder, then they're the people to fix it.

Cheerio,
Aaron.

[Servo]

To answer you question yes VTbuilder can load the dem files.

here are two images the first one is of the west coast hightmap
downloaded from the same server.




And this is the second image of the DEM hightmap for Canada I downloaded and keep having problems loading in VTbuilder.

This is how it looks you can see how messed up it is.

[Aaron]

Hi Servo,

It looks like VTBuilder is expecting a different scanline width to that which is in the file. This could either be a VTBuilder error, or it could be that the width reported in the DEM file header is different to the actual width of the height data scanlines. As I have no great insight into DEM formats or the internal workings of VTBuilder, I suggest you contact the VTP mailing list. By the way, did the VTP logfile show anything interesting?

Cheerio,
Aaron.