Ways to determine summit elevations (outside USA)

I am currently in the process of writing guidebook descriptions for various mountain hikes in my area. I am using www.OpenTopoMap.org to find summit elevations, or as close as I can get. The contour interval is 10 meters, but the actual elevation for the summits of interest are not listed. Up till now I have been using the highest contour on the map as the peak elevation. I know some people advocate assigning the summit elevation as x + half-the-contour-interval, where x is the highest contour. In my case that would mean adding 5 meters. I have been considering this approach, but I wonder if I can do better.

Is there a way of querying GIS data to get a (more) accurate summit elevation?

One of the mountains I am writing up has a highest contour of 3,430 meters, but since it is a steep cone, the actual top may be 20-30 meters higher. A large number of sites on the internet give an elevation of 4,350 meters, which is definitely wrong. I think this must have come from someone who swapped the first two digits of 3,450, and the figure got propagated all over the net.

The peaks I am working on range in elevation from 2,500 to 4,000 meters, in an area where the highest mountains are over 5,000 meters. They are all located in China's Yunnan province.

The simple solution is probably to hike up to each summit with an altimiter or GPS. That is not an option for the near term, so I'm hoping there may be something I can do with GIS, but haven't a clue how to go about it.

If they have not been surveyed, I doubt you will get better estimates than 1/2 the last contour. If it was me (and I am writing a book about hiking!), I would state the method I used in the front of the guide and leave it at that.

I don't know anything about the Chinese government approach to mapmaking, but I doubt they have any more useful data than what's already on your maps. You can find elevation data sets from, say, the Shuttle Radar Topography Mission, but that's useless for determining the heights of peaks - the resolution isn't nearly good enough. If the number of peaks you care about is limited, then hiking each one with a good GPS and barometer is probably your least-effort option. Other than that you can try your hand at trigonometry - either from the ground, or using a large set of aerial photos. But that's very tedious and error prone and you'll need a large number of measurements to have much confidence, so you're probably better off just measuring the peaks directly.

In the meantime, I'd list them as last contour plus, e.g. "3450+". Give exact numbers only when you are confident in them.

Perhaps this link will help you a bit: https://algorithmia.com/algorithms/Gaploid/Elevation

For more info check out OpenStreetMap Wiki page on SRTM: https://wiki.openstreetmap.org/wiki/SRTM and ASTER: https://wiki.openstreetmap.org/wiki/ASTER (the latter b/c of reference on WaymarkedTrails page at https://hiking.waymarkedtrails.org/help/rendering/elevationprofiles .)

nartreb said:

I don't know anything about the Chinese government approach to mapmaking,

Click to expand...

From what I gather, it's illegal for private individuals to make maps in China and the gov't ones that are out there are purposefully inaccurate for "reasons of national security"