Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Not sure if I would go for it, but… "Precision for the location of the center should be one percent of the square root of the area covered." Oslo covers nearly 1000 km², that would give 1 % of 32 km or 300 meter or 0.3 arc seconds. On Mon, Nov 6, 2017 at 2:50 AM, John Erling Blad

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Glittertinden, a mountain in Norway have a geopos 61.651222 N 8.557492 E, alternate geopos 6835406.62, 476558.22 (EU89, UTM32). Some of the mountains are measured to within a millimeter in elevation. For example Ørneflag is measured to be at 1242.808 meter, with a position 6705530.826, 537607.272

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

The GPS unit on my boat regularly claims an estimated position error of 4 feet after it has acquired its full complement of satellites. This is a fairly new mid-price GPS unit using up to nine satellites and WAAS. So my recreational GPS supposedly obtains fifth-decimal-place accuracy. It was

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Hi! > The reason why we save the actual value with more digits than the > precision (and why we keep the precision as an explicit value at all) is > because the value could be entered and displayed either as decimal > digits or in minutes and seconds. So internally one would save 20' as >

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

And thanks for the use cases. This helps a lot with thinking about this. On Thu, Aug 31, 2017, 16:31 Denny Vrandečić wrote: > The reason why we save the actual value with more digits than the > precision (and why we keep the precision as an explicit value at all) is >

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

The reason why we save the actual value with more digits than the precision (and why we keep the precision as an explicit value at all) is because the value could be entered and displayed either as decimal digits or in minutes and seconds. So internally one would save 20' as 0.3, but the

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Hi! > I am not sure I understand the issue and what the suggestion is to solve > it. If we decide to arbitrarily reduce the possible range for the Well, there are actually several issues right now. 1. Our RDF output produces coordinates with more digits that specified precision of the actual

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Hi! > 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

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Hi! > relied on unless there's a guarantee certain set of data (e.g. all > observatories) have the same accuracy and it is kept up-to-date. > >   > Like in all the wiki-world, this should be guaranteed through the > reference claim, shouldn't it? No, reference only says where the data

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Now the spatial reference That's what folks should discuss about. That's a real need, but I think is already solved with an existing property ? or even identifier system ? -Thad +ThadGuidry On Thu, Aug 31, 2017 at 4:30 PM Thad Guidry

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

> > Having it all queryable in Wikidata ? hmmm... not for me, other data > > catalogs and GIS systems handle that job. > > Exactly. > > Glad you agree. :) Once someone comes up with a REAL usecase and not hyperbole, then we can get to work...until then. GIS systems do the job quite well, and

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Hi! > For one reason...There are already tons of public LIDAR datasets with > point data down to millimeter. > I've even seen monuments and public art sculptures that have LIDAR > datasets down to millimeter precision using WGS84 base references. OK, but: 1. For objects we store in wikidata,

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

On Tue, Aug 29, 2017 at 2:13 PM, Stas Malyshev 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

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

You'll want to get down to millimeter. For one reason...There are already tons of public LIDAR datasets with point data down to millimeter. I've even seen monuments and public art sculptures that have LIDAR datasets down to millimeter precision using WGS84 base references. (think knowing the

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Hi! > transformation to WGS84. Some places like important peaks or astronomy > observatories can be located with such precision. True, but this probably won't be kept up-to-date and most likely would be useless for Wikidata users since random very precise data can not be relied on unless there's

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Hi Stas and wikidatans, the coordinates with (sub)millimeter precision might be imported from external dataset. With precise geodesic measurements, it is technically possible to reach such precision, yet it often decrease significantly by transformation to WGS84. Some places like important peaks

Re: [Wikidata] Coordinate precision in Wikidata, RDF & query service

Stas and All, Would the coordinate precision in Wikidata and Query Service allow us now to move to the cellular and even the atomic and subatomic levels, say, for example, when querying for differences between microscopic species in a piece of earth in a municipality that might be rich in

[Wikidata] Coordinate precision in Wikidata, RDF & query service

Hi! I would like to initiate a discussion about coordinate precision in Wikidata and Query Service. The reason is that right now we do not have any limit to precision, coordinates are basically doubles, and that allows to specify over-precise coordinates and makes it harder to compare them - both