TransDEM Forum

Good Day Dr. Ziegler,


I recently got the itch to make a mini DEM and I ran into a small issue with the map tile servers. In the past, MS Virtual Earth and Google Maps have both worked fine for me but I tried to make some tiles tonight and found that only MS Virtual Earth works. Google Maps will show maps but not orthophotos. In the past, I could compare the quality of the tiles between these providers and choose according to my needs (in my limited experience, I found Google Maps did better in rural areas whereas MS Virtual Earth did better in suburban or urban areas). Anyhow, I am wondering if this is a known issue. It is not a major problem, since it seems like MS Virtual Earth is working fine, but I would love to be able to have the best option and am wondering if there is something I am missing. Or does it have to do with the area I am trying to model? I shall test that out now...

I believe I downloaded the most recent map tile server settings (In January, 2014) but I could be mistaken.

Any help would be most appreciated. Have a great day!


Mr. Gisa
edit: confirmed that google maps does work, perhaps this is due to security issues in the area I am modelling. MS Virtual Earth it is...

I still guess, it's Google. MS Bing/Virtual Earth should be okay. Google uses versioning for ortho-photos. The version umber is part of the URL. These numbers are changing rather quickly. The latest, as of today, is 202.

Here is how to set it: http://forum.transdem.de/viewtopic.php?f=7&t=364 (Substitute "174" with "202".)

Thanks for your help Dr. Ziegler. I did change it to 202 and it seemed to work fine. MS Virtual Earth seemed better in comparison, so I'll use that provider.

Out of curiosity and for future reference, how often do the numbers seem to change? How could one find out what the latest number is?

Gisa ^^

They tend two change very two weeks or so. But Google retains a couple of versions back, so you don' have to adjust at the same frequency.

How to find out the latest version the simple way:

Go to the "URL composition" dialog again, where you adjust the version number. Down at the bottom you'll find a sample URL. By default it's Sample 1 and for Australia. Sample 2 points to Florida and sample 3 is Aachen where I live.

Copy the sample URL to your web browser. In your browser edit the URL by increasing the version number until it yields a result again and then further up until it produces 404 again. Use the highest version number that succeeded for the "query prefix" in the TransDEM settings page.

Thanks for the advice Dr. Ziegler. Now I, and others, can use Google Maps if need be.

Mr. Gisa ^^