.CSV format elevation maps for Litchi for areas OTHER than the USA?

[Dan C]

NOTE: Not seeking files for the USA.

I've been searching for these elevation data files, specifically for China, but I cannot for the life of me figure out where to get them. Every resource I've found so far offers multiple files for things like "roads", "water", "points of interest". This doesn't seem right. I just want ground elevation data.

Researching the subject, I discovered, "The .zip file must contain at least the .shp, .shx, .dbf, and .prj files components of the shapefile." The aforementioned roads and points of interest files I found for China have these formats, plus a small .cpg file.

But Litchi says .CSV or .KML only. (I have used the .KML option in both directions with Google Earth Pro, but this is not a viable option for China -- way too few features are 3D in GEP).

Can anyone point me towards a .CSV file that covers China, or better yet, one where I can choose the area(s) I need?

 

[Keule]

Can anyone point me towards a .CSV file that covers China, or better yet, one where I can choose the area(s) I need?

You have to do the required steps to get the desired data on your own:

First, get a DEM from the desired area:
You can search and download them from USGS EarthExplorer (Data Sets -> Digital Elevation -> SRTM).

SRTM at 1-arc second resolution is available for China. The spatial resolution is approximately 30m. Vertical accuracy, like any SAR DEM, varies with topography and land cover.

Second, convert the acquired DEM to text. (WGS-84 ESRI ASCII Grid).
Use Global Mapper or similar software.

Then you can load the dataset into Litchi.

 

[Dan C]

You have to do the required steps to get the desired data on your own:

First, get a DEM from the desired area:
You can search and download them from USGS EarthExplorer (Data Sets -> Digital Elevation -> SRTM).

SRTM at 1-arc second resolution is available for China. The spatial resolution is approximately 30m. Vertical accuracy, like any SAR DEM, varies with topography and land cover.

Second, convert the acquired DEM to text. (WGS-84 ESRI ASCII Grid).
Use Global Mapper or similar software.

Then you can load the dataset into Litchi.

I've put hours into trying to follow your advice, but I keep running into two inter-related problems.

I'm offered multiple choices on the types of files to download. On the USGS site, there are multiple ways to download "something", but I don't understand the different formats.

And there doesn't seem to be a translation utility out there. All I've found are mapping programs which include the ability to import/export in different formats. Trouble is I have no clue how to use these things. It's not like a photo editing program where you simply load one format, then "Save As" to your desired format.

I can't even tell if I'm actually loading the files right, or if I'm loading the right files.

Of course, I'm not dropping $500 on Global Mapper when I don't need any of what the program can do -- and have zero idea how to use it, or even what it does -- but I have downloaded and installed a few free mapping applications. And even these I just can't drive. I seem to have succeeded in opening different formats of files, but I just can't get anything out of them, and I suspect there is some other step(s) I need to do. Like the data is in the program, but not really "loaded" yet... If that makes any sense. Probably doesn't, but you see how much I'm floundering with this stuff.

If anyone can tell me:

• EXACTLY which file(s) to download from USGS. And this will include the download steps; as I said, I've poked around and found a couple of ways to, well, get a result, but these four or five different formats mean nothing to me.
• Point me towards a basic conversion tool. I neither need, nor understand the mapping programs that include the ability to convert.

Or... Just a source where I can download the elevation data I need that is ready to use with Litchi.

@Keule steps get me part of the way, and I seem to have successfully selected the geographic area for data, but after that I have too many options. I don't know what I need, I don't understand the file types. My "blind flying" eperiments haven't succeeded so far.

Thanks in advance people.

 

[Keule]

I don't know what I need, I don't understand the file types. My "blind flying" eperiments haven't succeeded so far.

Download GeoTiff files from USGS.
You can use online Converter like this one to get ESRI ASCII output.
Be sure to use the correct coordinate system for China. (GCJ-02) and not WGS84.

Just curious, what is your use case?

 

[Dan C]

Just curious, what is your use case?

Nothing very exciting. I live in Central China, and I have a few challenges I'm trying to resolve. Mainly, within Google Earth Pro the number of 3D buildings in my city is minimal, so I don't get much elevation planning assistance there. And using a VPN, particularly on cell service, can be problematic, so reliance on online elevation data is also questionable.

Add to this situation the fact that authorities are somewhat paranoid about foreigners, and a foreigner with a drone amplifies that a lot.... So, while I'm obeying local laws, and have my drone registered, I'd prefer to avoid being seen flying.

My use case is videography. I'm capturing footage to make a documentary about my city. Once I've got that experience under my belt and can plan (I hope) more efficient forays, I want to go visit several other cities (one weekend for one city).

So, I need to be able to plan missions with higher confidence, sight unseen. When I arrive on location, a quick visual check to ensure there isn't anything new in the way (high probability), then launch the mission and promptly move on before curious locals mob me. You might not believe just how hard it is to find a launch location in public where you aren't surrounded by people, or won't become that way in minutes.

In short, I'm making films, and want to make my process safer, with higher confidence in the mission, and get in get out as fast as possible.

BTW, I now have a large blue square over most of my city in Litchi Mission Hub, so I'm thinking I've succeeded. I've got to test it yet, but thank you for your assistance.