Using Srtm Data Instead Of Google Earth Kml Files?

All the route building tutorials start with .kml data downloaded from Google Earth. Is there a way to use directly downloaded SRTM data instead?

 

I'm beginning to wonder about this too because I'm having a lot of issues and a lot of them seem to be pointing to the use of .kml instead of a .hgt file

 

My second go at making a route didn’t use the kml file at all. I think it’s only use is in marking out the position of the main track in the route and then it helps automate the process of creating tiles along and to either side of that track.
It’s perfectly possible to create each tile individually with reference only to the SRTM file.

 

Did you follow a guide on how to do that?

 

Yes try this guide and ignore all references to LiDAR files if you don’t intend to use it at the moment. Only the SRTM file is really necessary to get started.

The good stuff using the editor starts at around 12 mins.

 

The .kml data isn't actually downloaded from anywhere. It's just a collection of markers and paths used to define the route's extent.

Just draw a path (or multiple) that represents you route, then place a marker over every station and it's all set.

note: The order of the markers in the Google Earth outliner actually defines the order of placemarks in the editor so it's a good idea to give them a sensible order.



As always, I suggest watching the whole editor stream as it contains a whole load of useful information.

 

Yes, but I don't have Google Earth Pro. Is not having any .kml data going to be an issue?

 

PC version of Google Earth Pro is free to download. Is there some other issue?
https://www.google.com/earth/about/versions/

 

Oh, I assumed from the title it was paid.

 

You can use google earth browser edition, no need to install earth pro.

 

For faster rendering, it's best to use Google Earth Pro desktop version. Also best to use the desktop version in case your internet decides it's had enough and went off to have a cuppa tea and kit-kat without inviting you!

 

I tried that but the exported KML surprisingly uses somewhat different syntax and did not work for me in the tsw editor, so I switched to earth pro. How did you get it to work?

 

in my guide I show how to get kml but I need to change things around because I've had a lot of issues using the kml for terrain. I've found terrain is better with strm (.hgt) format. but I still use my kml for placemarks Using the .hgt I find better as well because you can create 1 tile at a time and add your lidar to it which makes sure you only get the areas you need https://docs.google.com/document/d/...xo8P6djUyCb1jPX13D1AbdYm3PapxTof-Q-7RdG3C/pub

 

The .kml file you obtain from Google Earth Pro is just for reference and to give you a guide in both QGIS and the PC Editor to know where the route is (for placing/creating tiles, applying Lidar data or just selecting the Lidar tiles close to your route in QGIS) + actually gives you the placemarks in the editor (which can be a huge time saver for longer routes if you just can jump to a certain place and don't have to load in the Google Maps data to orientate where you are and where you have to go).

The SRTM (.hgt file/s) - for low resolution - and Lidar data (.tif/.asc file/s) - for high resolution - are the only ones which contain the Digital Elavation Model (DEM) / Digital Terrain Model (DTM) - in Germany "Digitales Gelände Model" (DGM).

I think I found the reason why many people actually think that the .kml file from Google Earth Pro shall contain the DEM/DTM.

It is because of the misworded and confusing commands to create the landscape within the editor as showed in the masterclass tutorial and used by DTG Lukas.

The commands are (highlighted the confusing words):

"ts2ed.experimental.CreateSceneryAndLandscapeTilesFromKML 3"

and

"ts2ed.experimental.CreateTrackTilesFromKML 1"

But that makes absolutely no sense, since the tiles and the landscape aren't created from the KML file, as rather the SRTM data in the HGT file for the low resolution height profile of the landscape.

So, the commands technically shall be called:

"ts2ed.experimental.CreateSceneryAndLandscapeTilesFromHGT 3"

and

"ts2ed.experimental.CreateTrackTilesFromHGT 1"

Confusing....

So, technically if you want to omit these guides (but it is definitely not recommended), you don't need a .kml file at all.

The only thing you really need from Google Earth/Maps to create your route are the coordinates of the point of origin/point of reference in your route.

 

I don't find it too confusing. The command just looks at the kml paths and creates tiles within a certain distance. The fact that newly created tiles get auto-filled with SRTM data is a different process.

It's more of a matter of people not knowing the contents of files they are working with.

KML - vector lines and markers
HGT - low-resolution heightmap. Normally with resolution of 1 arc second or about 30 meters per pixel.
ASC - high-resolution heightmap. Must have 1 meter resolution.

 

I created the tiles for the first time without any SRTM data accidentally. I know that the Editor just can create tiles with this command. However, these ".kml tiles" are just plain and even tiles with no elevation data in it.

I don't think that the tiles created from that command are built up around the route because of the data in the .kml file. From what I've seen it just creates tiles based on the location you are in because of the coordinates you entered when creating the route.

This is what I meant.

Therefore, the term "CreateSceneryAndLandscapeFromKML" is confusing and even wrong because in fact, it doesn't create scenery and landscape. In my opinion, this is exactly what brought some people to thinking the .kml files might have some DEM/DTM information in it.

 

I recommend you use .KML. This saves you a lot of resources and time, if you don't also generate useless tiles