Hi all,

I experience geospatial datetype decision problem. We use for a while geo:lat and geo:long as xsd:decimal as I was not able to find correct datatype and xsd:decimal seemed quite solid. Now I see in Sesame that they use xsd:double ( https://openrdf.atlassian.net/browse/SES-1808 ). Then I looked into FactForge, did some random query which returns latitude and longitude and export some lines into JSON. There I see that some are float, some are double and some dont even have a type :

{
    "latBase": { "type": "typed-literal", "datatype": "http:\/\/www.w3.org\/2001\/XMLSchema#double", "value": "51.5084152563931" }, 
    "longBase": { "type": "literal", "value": "-0.12883186340332" }
}, 
{
    "latBase": { "type": "literal", "value": "51.5005149421307" }, 
    "longBase": { "type": "literal", "value": "-0.12883186340332" }
}, 
{
"latBase": { "type": "typed-literal", "datatype": "http:\/\/www.w3.org\/2001\/XMLSchema#double", "value": "51.5084152563931" }, 
"longBase": { "type": "typed-literal", "datatype": "http:\/\/www.w3.org\/2001\/XMLSchema#float", "value": "-51.128055555555555" }
}

My next stop was Google recommendation and for MySQL they recommend float. We want to have standard implementation as I see that in future releases you plan to be in sync with some geo standard and we don't want to risk that all geospatial function (omgeo:nearby, omgeo:within...) will stop to work. What is your advice?

Thank you for your answer.

Best regards,

Marek

asked 22 Apr '13, 08:56

Marek%20%C5%A0urek's gravatar image

Marek Šurek
161212127
accept rate: 0%


OWLIM is quite flexible. It just required that the lat/long literals are numeric. I think you will be quite safe typing them to xsd:float or xsd:double if you need the extra precision.

link

answered 23 Apr '13, 17:10

baz's gravatar image

baz ♦♦
33128
accept rate: 36%

So no exact standard for lat, long representation right?

(24 Apr '13, 04:33) Marek Šurek

Not in OWLIM and I'm not aware of a standard for this anywhere else. I had a look through http://www.opengeospatial.org/standards/geosparql but I didn't find anything.

(29 Apr '13, 07:34) baz ♦♦
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Asked: 22 Apr '13, 08:56

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Last updated: 01 Jun, 04:22

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