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why can't you use better elevation data?

+1 vote
I own several challenge caches that require people to find caches in certain elevation bands, GC3K0T3, GC3K0T7 and GC3K0T9.  Recently it has come to my attention how bad the elevation data that project gc uses can be.  I read the explanation in the FAQs tell where the data comes from but it doesn't really address why the site can't get better data.  For example GCGTCH, It's a Long way up! is on the summit of Longs Peak in Colorado at 14,255 feet.  The altitude the the site assigns to it is 13871, that's 384 feet lower than the actual elevation.  Groundspeak wants us to use checkers on project gc but it's frustrating for owners and cachers alike when the data is that far off.
asked Oct 13, 2017 in Support and help by WingsAndTales (130 points)

2 Answers

+1 vote
As much as I'm with you with those frustratingly off elevation data, I fear there isn't a global, reliable and accessible database for elevation data, as there aren't measured date for every possible co-ordinate.

Even the best resolution available (30m x 30m) leads to areas of almost 100m² where no true data exists.

Project-GC can't add or correct elevation data manually and as long as does not provide elevation or an option to add them in the cache listing (but who would control the entries made there?), this is all we have.

I wish there were better data...
answered Oct 13, 2017 by clappy (1,210 points)
So why is it that I can put coords into Google Earth or run an elevation macro on GSAK and get better info.  They still aren't perfect but if they are off it's by tens of feet rather than hundreds?  Are the databases that those sources use not available?
+2 votes

why the site can't get better data

Do you know about some other source, that would be freely available to use in other tools, such as If so, please, share the knowledge and I believe we will be very happy to use more accurate elevation data.

The solution of Google Earth is either limited (to 2,500 caches per day) or paid. Refreshing all the caches in database would certainly not fit into the free bucket, but after downloading and caching the data for existing caches, pulling the daily-new ones should be "pretty cheap".

I believe is mainly based on freely available tools and sources unless there is a strict limitation or a other need. I saw some elevation inaccuracies, but nothing significant (though it can be different in other parts of the world).

Using GSAK elevation database could be also an interesting alternative, though it does not speak about the usage policy it can be used for.

answered Oct 14, 2017 by Jakuje (Moderator) (69,570 points)