I often encounter the problem that the coordinates of mountain summits are incorrect, usually due to an incorrect USGS topo map that served as the basis for data. When I want to go in and edit the location to be more accurate, based on actual in-field observations, I found I could not simply update a “latitude” and “longitude” field the way I could, say, change elevation or the name.
Did I just miss something? It seems very strange to me that a geospatial tool that relies on precision would be so imprecise. What’s worse, not only could I not just enter the coordinates, as I was moving the point around, I could see nothing that told me where I was moving it!
Slightly off topic, but how are you making the measurements for your “in-field” observations?
I would generally expect a professional survey by a national mapping agency to be done to far greater accuracy than is available from consumer hardware.
You could also download the object in XML, then edit the text file directly, then open that in JOSM and upload (but I’ve never tried that, there might be missing steps)
In this case I can see that the summit marker was placed on the USGS topo map’s summit marker, but my track and many other tracks I’m reviewing all agree and show that the underlying map data is incorrect. To try and position myself in the field at what the USGS says is the summit marker would require me to go downhill.
A professional survey by a national mapping agency would be far more accurate than consumer hardware, but that’s not what OSM has. OSM’s mountain peaks in the United States are based on the GNIS import, and GNIS is mostly derived from digitization of paper maps, with errors of tens of meters being common.
If you want professional survey results, you want the US Geologic Survey’s database of benchmarks. But not every mountain peak has a benchmark, just the ones that are useful for surveying.
Very important to be aware trig points and benchmarks may not be at the highest point of the mountain for various reasons, especially surveying visibility. So they are best verified and added independently.
