TransDEM Forum

G'day geophil,

Roland, I am trying to add two adjacent pre-saved DEM files together (created by myself from greater wholes), each of which covers an area of a little over half a latitude 'wide' and when joined, would be almost a full longitude 'high'. Sourced from the USGS NED 1/3 arcsec resource, each of these files is about 120 MBytes apiece and comprises the bare minimum amount of data to cover the required area but no matter which way I try to attack the 'mating', I always get the "Crash Dump" error and the subsequent 'failure' of TransDEM. I realise that you provided the "Crash Dump" 'facility' to help solve issues like this but there doesn't seem to be any instructions or 'direction' on how these files might 'get into your hands' to allow for this. I suspect I know the cause of this problem but I would very much like to have your 'interpretation' of the "Crash Dump" files I have thus far 'collected', so that this suspicion can be confirmed or denied. How should I get them to you (and which should I send) for your appraisal of the situation?...

Jerker {:)}

Hi Garry,

there is no automatism here. The popup message will notify you of the intercepted crash and tell you the location of the files but TransDEM - or what's left of it after a crash - will not send them anywhere.

By default, the location of the crashdumps is (for 2.6.0.2 64bit):
C:\Users\<user name>\AppData\Local\CrashRpt\UnsentCrashReports\TransDEM Trainz Edition (64bit)_Version 2.6.0.2

There are zipped and unzipped versions, just send me the zipped one. The dump files are rather small, they only record the call stack and local parameters for each thread, but in certain cases this is enough to identify the problem.

G'day geophil,

I am well aware, Roland, that nothing in this situation is automatic but that's the thing - HOW do I "send" things to you and exactly what do I send? There is an executable in the TransDEM root folder called "Crashsend1403.exe", do I use that or a more 'traditional' method? From the specified location, do you want the entire folder ("TransDEM Trainz Edition_Version 2.6.0.2") or one of the individual 'reports' (which appear to be *.xml files) from within it? I am at a loss, so some clarification is needed...

Jerker {:)}

That crash sender exe needs to be there for the crash dump collector to work but won't be called by TransDEM.
Simply attach the zip file(s) to an email, that's easiest. The sub-folders are just unpacked zips (apart from the log folder).

G'day geophil,

Ok, I've got all that, Roland but which *.zip file(s) do I send you. I have accumulated a large number of these...



...so which one(s) do you want?..

Jerker [:)}

The latest will probably do, if they all indicate the same problem. Switch to the "details" view in Explorer to sort them by date.

G'day geophil,

...Roland, you have e-mail. I have sent the four most recent zipped files I have...

Jerker {:)}

Garry, I had a look into the crash dumps. The post mortems are quite short, very short indeed, but it appears to be an out-of-memory problem. And while I added several checks for memory allocation, there may still be a few places, where an allocation may fail without being noticed immediately. But milliseconds later TransDEM will most likely crash.

You are running the 32bit version of TransDEM. And there, process memory is limited to 2GB, or, with a tweak, to 3GB. See pages 21/21 in the 2.6.0.2 TransDEM main manual.

I a not sure whether the 3GB option will make it possible to merge two of the 1x1 degree 1/3 arc sec DEMs. It may work, it may not. If it doesn't, you can cut down the DEMs to the area you are really interested in before attempting to merge, either when opening the original DEM in TransDEM the first time, or afterwards, one it has been loaded and converted to UTM.

G'day geophil,

I had a feeling you were going to say something like that, Roland. Indeed, I do still utilise a 32 bit system and although I have 4 Gigabytes of physical memory installed in the machine, I haven't made use of the 'tweak', so the system only sees the 2 gigabytes that shows up in the crash reports. I have good reason not to have applied the 'tweak', for, you see, the last time I tired to use it, my whole system failed and it took me ages to get it back to rights. I have no idea why it should have had that effect, I know it works, from my own experience, I have the 'tweak' applied to my laptop and there, it worked as it should (on the first attempt) and TransDEM is not the only source I know of recommending the 'tweak'. You will understand, I am somewhat reluctant to use it again...

...the DEM file isn't the full two 1 x 1 degree tiles (as I may have already mentioned). They extend the "width" of two tiles but only the "height" of one tile, going from the SW corner of one to the NE corner of the other and I have, as I said, trimmed them to the barest minimum I dare, to match the 'shape' of the baseboards covered by the Topographic maps. They are both about 130 Mbytes apiece (give or take) but they are still bringing the system to its knees...

...I will attempt to reduce their size further to see if that will solve the problem...

Jerker {:)}

What is your grid width for these 1/3 arc sec DEMs in UTM? 10 or 5m? 5m would quadruple the memory needed.