On Tue, Aug 29, 2017 at 2:13 PM, Stas Malyshev smalyshev@wikimedia.org wrote:
[...] Would four decimals after the dot be enough? According to [4] this is what commercial GPS device can provide. If not, why and which accuracy would be appropriate?
I think that should be 5 decimals for commercial GPS, per that link? It also suggests that "The sixth decimal place is worth up to 0.11 m: you can use this for laying out structures in detail, for designing landscapes, building roads. It should be more than good enough for tracking movements of glaciers and rivers. This can be achieved by taking painstaking measures with GPS, such as differentially corrected GPS."
Do we hope to store datasets around glacier movement? It seems possible. (We don't seem to currently https://www.wikidata.org/wiki/Q770424 )
I skimmed a few search results, and found 7 (or 15) decimals given in one standard, but the details are beyond my understanding: http://resources.esri.com/help/9.3/arcgisengine/java/gp_toolref/geoprocessin... https://stackoverflow.com/questions/1947481/how-many-significant-digits-shou... https://stackoverflow.com/questions/7167604/how-accurately-should-i-store-la...
[4] https://gis.stackexchange.com/questions/8650/measuring-accuracy-of-latitude-...