Tracklogs V3.12 is now available for download, which reminded me to post an entry about a problem with their DEM (Digital Elevation Model): it is truncated in the far north. This only affects the latitude of the Shetland Isles and northwards. The southern part of the islands shows the correct elevation data in the status bar, but the northern part does not - it always shows 0m. The truncation can be seen by saying View — Goto and entering the grid reference HU 404 673. The elevation data is shown correctly in the status bar at this point, but move the cursor northwards and just above here it drops to zero.
Another interesting and related problem, possibly due to the same cause, is that the crosshair in the navigation pane is also limited in range - it won’t go that far north. The Shetlands are outside the pane, which is why I had to use the grid reference (obtained from Memory Map) to get the map displayed in the main pane.
Tracklogs Support say it may be due to the range limit of the satellite scan done by NASA, which has me confused about the source of elevation data for the various software packages. Memory Map uses OS elevation data - this is complete in the far north of Britain and not truncated, I thought Tracklogs used the same source. At one time Fugawi mapping used the very coarse SRTM height data but now claims to use ‘ Enhanced elevation data for Great Britain’ for the UK version which I presume is the OS data.
Tracklogs say they are about to review the data so we may see a new issue of the DEM in the near future.
One Comment
I have found another problem with the new version, where copy/paste of trackpoints results in each of the new points being linked by a new piece of track to the first trackpoint in the original resulting in a right mess. Tracklogs have reproduced the problem and come up with the following workaround:
As a quick follow up.. we’ve identified the problem cause and if you
need to workaround this whilst we get the fix out then there is a
technique. The bug is that the pasted in trackpoints are being linked to
point zero in your existing route (usually the first point you draw or
the first point from the GPS). If you locate and delete this point then
recreate it you effectively rid the route of a valid point zero so the
bug can’t incorrectly connect all the pasted points. Fiddly but will get
you up and running whilst the full fix is tested.
John