Thailand does not seem to have official guidelines for elevation sources or accuracy. For OpenStreetMap contributors, what are the best sources and methods for adding or verifying peak elevations in Thailand?
According to ChatGPT, some commonly used global sources include:
SRTM (30m resolution) – Decent but has errors in steep or forested areas.
ASTER GDEM (30m resolution) – Sometimes noisier than SRTM.
Copernicus DEM (30m and 90m) – Better in some cases.
GPS/barometric altimeter readings – Can be inconsistent but useful for relative corrections.
Are there any recommended workflows or locally available datasets that provide better accuracy? What do mappers in Thailand typically use for peak elevation data in OSM?
In the absence of official peak elevation data, I’d not add values to OSM.
For apps that need elevation data, they can use SRTM, Aster or whatever source they wish directly.
For my topographic maps that is what I do. My scripts will grab the digital elevation model (DEM) or equivalent from one of several sources and use that for generating contour lines, slope shading, etc. I could probably have high point elevations labeled to. If there is a spot elevation in OSM I expect it to be from an official geodesic data source.
Are there any well-known apps that use SRTM to determine peak elevation when the tag is missing? I checked Komoot and AllTrails, but they don’t.
I don’t think this aligns with the open nature of OpenStreetMap. Some data is better than none. Similarly, we map administrative boundaries without exact coordinates (which don’t exist in Thailand anyway) and add roads that are missing from official maps but visible in imagery or traceable from approximate GPS data.
Having non-official elevation data for peaks is better than having none, as it provides end-users with a useful reference for elevation changes—something that can be hard to gauge on maps with limited contour labels.
With the NOAA EOSDIS plugin for JOSM you get a gradient layer AND a readout of the elevation in the status bar at 10cm ele precision anywhere the mouse pointer goes. Done verifications against lots of documented peaks and it checks. Use it mostly to determine incline direction for road tagging and flow directions of streams mapping. Since the waterway map has little to complain, no defiance of gravity.
Right, we’re not supposed to copy details from the Royal Thai Survey map, and at the same time, I’m not sure how reliable they are anyway—boundaries and roads are often inaccurate.
However, I think we can reference Wikipedia when available and link to the article. For example:
