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I have extracted these coordinates from geolinkedata And I don't know what system they are using:

(-15.4400797 28.131791000000003)

What I know is that they correspond with these WGS84 Coordinates:

(39.4723047, -6.3734381)


Introduction:

I am trying to use the SPARQL interface of linkedgeodata (2) to match some streets names I know, with instances of streets in their SPARQL Endpoint. To do so, I need to filter all the streets to keep only those that are placed in the surroundings of Cáceres.

If the coordinates of the streets in the SPARQL interface of linkedgeodata (2) were in WGS84 I wouldn't have any problem, because I understand those coordinates and I know how to work with them.

The problem is that I really don't know what system they are using, that's why I searched a street manually:

http://linkedgeodata.org/page/triplify/way230844225

whose first node is:

http://linkedgeodata.org/page/geometry/node337348441

Which has the following coordinates:

(-15.4400797 28.131791000000003)

Then I searched this same street in the OpenStreetMap (which is where the data of linkedgeodata comes from):

https://www.openstreetmap.org/way/32934574#map=18/39.47217/-6.37171&layers=QN

I saw the coordinates in wgs84:

(39.4723047, -6.3734381)


Problem:

This approach I used was possible because I knew this street beforehand, so it is not replicable to all the other street names.


What I need:

I need to know what kind of coordinates are (-15.4400797 28.131791000000003) to convert all the other streets' coordinates automatically to WGS84, the format I understand and the one I feel comfortable working with.

NOTE: As my reputation in this web is 1, I can only post 1 link in the whole post, thereby the weird links, sorry for the inconvenience.

(2): http://linkedgeodata.org/sparql

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    Welcome to GIS SE! Please provide additional information about the coordinates you have extracted, and the method, how exactly the extraction went. The LinkedGeoData browser shows the correct WGS84 coordinates for Cáceres. – Gabor Farkas Jun 2 '15 at 12:39
  • @GaborFarkas I hope this time the question is suitable. – Jesus Jun 2 '15 at 17:28
  • Absolutely! The problem is reproducible, but I couldn't find a solution in neither of their readme files, and descriptions. Maybe there is someone here, who already solved this problem, or alternatively, you could just ask them. – Gabor Farkas Jun 2 '15 at 18:08
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I think you looked up the wrong way:

https://www.openstreetmap.org/way/230844225 in Las Palmas de Gran Canaria.

has the same way ID as the linkedGeodata.org dataset, but accidentally the same name as

https://www.openstreetmap.org/way/32934574 in Cacares, Extremadura.

And the node https://www.openstreetmap.org/node/337348441 still exists in the OSM database, with coordinates 28.131791, -15.4400797

Note that OSM displays the data in lat-lon order.

  • WOW! I was pulling my hair out with this. I fell in the same trap I was trying to avoid (failing in the matching process). You're invited to a beer if you ever come near Pizarro street (in Cáceres, just for clarification ;) ). – Jesus Jun 4 '15 at 7:47

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