TransDEM Forum

Hello,

Using Transdem

a) I created a route
b) I used the map tile servers, but instead of using the providers google maps/open street map, tile type - map, I wanted to try the provider MS Virtual earth, tile type orthophoto
c) Map images along the path were created
d) Next step - I opened the dem file, raster map ( with the just created lgb.file ) and route.
e) selected ( mask ) the raster map and route
f) clicked on create a new map with Dem elevation and ground textures
g) received the error - error writing file - map files export

Does anyone know why this error appears when using a raster map ( created using provider MS Virtual earth, tile type orthophoto )?

Best regards

Kurt

Kurt, how many tiles did you load and what are the pixel dimensions of each tile? It could be a memory exhaustion problem. Despite TransDEM keeping the raster images in their compressed jpeg format until they are rendered, the amount and size of the images may eventually exceed available memory (2, 3 or 4GB, depending on your system).

Hello Roland,

Thank you for your reply.

I have a total of 71 tiles loaded. The size of the tile ( png format ) varies from 963Kb upto 1306Kb ). In total they represent 80Mb.

I did a comparaison with a raster map where I used open street map as provider and map as tile type. Here I only have 9Mb in total.

The total amount of mem in my pc = 8Gb . I think 4GB is available, but this is probably not enough.

Best regards

Kurt

I suggest to reduce the number of images and try again.

The actual memory usage is difficult to tell from the image file sizes because they are in compressed form. TransDEM needs to uncompress them when they are about to be rendered.

A good tool to monitor memory usage for an application is Sysinternals' Process Explorer.

Hello Roland,

OK - I will do some tests with smaller routes. I will give the results in a next reply.

Thank you for the sysinternals link - I will install the package and try it out.

Best regards

Kurt

Hello Roland,

I managed to find 2 small routes and did some tests with it
First route had 44 tiles (total size of png files = 45 Mb ).
Second route had 56 tiles ( total size of png files = 57,8 Mb ).

I could create a new map with Dem elevation and ground textures, of both routes.
Now, I have some idea what to expect. 71 Tiles ( total size of png files = 80 Mb ) is to much. For small routes I can use orthophoto with provider MS Virtual earth.

I also used the sysinternal VMMap ( memory check ). Looking at this check is already a big study.

Here is the result



Best regards

Kurt