Stuck on first step of creating custom topo

[sma12]

I have been trying to create according to the instructions from this forum here: Instructrions for Creating Topo Maps

 

Following the instructions, I go to SDDS and download a small "National Elevation Dataset (NED) 1/3 Arc Second" GeoTIFF file.

 

When I try to load this into Dem2Topo, I get an "Error encountered processing XXXX.tif" message. What am I doing wrong? Do I need to convert the GeoTIFF from SDDS to some other format for Dem2Topo to read it?

[+wesleykey]

The instructions can be printed in PDF from Cypherman's website

 

 

 

Evidently this is not a Groundspeak program or issue. Have you emailed this "Cypherman"?

[+Klatch]

The instructions can be printed in PDF from Cypherman's website

 

 

 

Evidently this is not a Groundspeak program or issue. Have you emailed this "Cypherman"?

Go to the main menu of this forum. How many of the threads are related to a "Groundspeak program or issue"? This is exactly the right place for his question.

[VTtrader]

I assume you have the IDL program installed that dem2topo needs to run, I'm not sure of the error message you would get if it's not installed. If it is installed correctly, then I would try re-downloading the .tif file. I have gotten several corrupted downloads. After downloading the file again, all was fine. IMO, that would be the first thing to try.

 

Let me know how it turns out.

 

Good luck,

VT

[+Hynr]

When you get the file from Seamless, it is a compressed folder (.zip). You need to open that (double click on it), find the large TIF file, and drag it out of the compressed folder into a regular folder. Then when you run Dem2topo in IDL, open that file.

[sma12]

I assume you have the IDL program installed that dem2topo needs to run, I'm not sure of the error message you would get if it's not installed. If it is installed correctly, then I would try re-downloading the .tif file. I have gotten several corrupted downloads. After downloading the file again, all was fine. IMO, that would be the first thing to try.

 

Let me know how it turns out.

 

Good luck,

VT

Yes, IDL is installed and dem2topo is running just fine with Canadian .dem files from the GeoBase web site. It also runs fine with .tif files created by 3dem from SDTS files. I just can't get it to work with the .tif files from USGS SDDS. I have tried downloading many different times from SDDS, always with the same problem.

[sma12]

When you get the file from Seamless, it is a compressed folder (.zip). You need to open that (double click on it), find the large TIF file, and drag it out of the compressed folder into a regular folder. Then when you run Dem2topo in IDL, open that file.

Yes, I decompress the .zip file and use the .tif file in the resulting folder.

[VTtrader]

When you get the file from Seamless, it is a compressed folder (.zip). You need to open that (double click on it), find the large TIF file, and drag it out of the compressed folder into a regular folder. Then when you run Dem2topo in IDL, open that file.

Yes, I decompress the .zip file and use the .tif file in the resulting folder.

 

I did have one other thought of what the problem might be. The dataset you are trying to use is significantly larger than the other ones you mentioned for the same area. You could be running out of memory trying to process the file. You might try downloading a smaller area as a test and see how that goes.

 

Good luck,

 

VT

[sma12]

Problem solved!! Thanks to all who helped. Thanks also to Cypher man, who offered help via email; I figured out the answer trying to respond to him.

 

I download from Seamless using Safari on a Mac. The file from Seamless unzips to a folder with a .tif file in it, "42796125\42796125.tif" for example. When I copy this to XP for processing, the file name shows up as "4279612542796125.tif", so I didn't notice anything odd. But apparently the backslash is still there, it just doesn't echo. This must look like a directory\filename to XP, which of course it doesn't find, and hence the error. If, on the Mac side, I just rename the .tif file to something without a backslash, it loads into Dem2Topo just fine.

 

Since people have generally not complained about this problem, I'm guessing that the file names must unzip differently in XP than they do on the Mac.

Edited September 26, 2007 by sma12

[Buckdown]

Ok , so I am having a problem myself with IDL Virtual Machine and Dem2TOPO . I downloaded the appropriate files needed and go through the steps up to the part where you "Create MP File" and it starts out ok , but then I get the "FATAL ERROR " message saying ......

 

" Something bad has happened : Unable to allocate memory to make array. Processing STOPPED "

 

I've read about changing the virtual memory settings on the PC and couldnt only find out much about this .

but I am using XP with a GB of memory .

 

Is there something I could do to fix this problem