We need to store coverage areas and search by location over arbitrarily large areas. It has to be able to handle polar searches and coverage areas that span multiple hemispheres. No GIS can do this. Informix has the Geospatial Datablade, but it costs like a hundred grand. Does anyone use something more affordable--preferably free?
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$\begingroup$ Meh, I'm not really sure that this is off-topic. I'm going to post a meta question about it (not that this is a bad question, I'm just not sure if software-recommendations are on-topic here). EDIT: Meta question asked: Are software-requests on-topic? $\endgroup$– hichris123 ♦Commented Apr 20, 2014 at 16:21
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2 Answers
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The best open-source and free geospatial database is in my opinion PostGIS. It is easy to use and has a huge support group (also for example at https://gis.stackexchange.com/)
It also connect to all sorts of different open-source programs and web-interfaces which should make data editing, viewing and sharing easy.
It can handle the date-line and the poles:
4.2.3.2.
What about the date-line and the poles?
All the calculations have no conception of date-line or poles, the coordinates are spherical (longitude/latitude) so a shape that crosses the dateline is, from a calculation point of view, no different from any other shape.
(http://postgis.net/docs/manual-1.5/ch04.html#id358535)
Link: http://postgis.net/
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3$\begingroup$ +1 for Postgres/PostGIS - this is the first question that is relevant to my day job :-) $\endgroup$– winwaedCommented Apr 20, 2014 at 21:56
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$\begingroup$ Last I checked, PostGIS doesn't support polar search, nor crossing the IDL. It makes the ubiquitous mistake of all GIS that latitude/longitude is a Cartesian coordinate system. The answer isn't as easy as that. $\endgroup$ Commented Apr 21, 2014 at 2:16
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$\begingroup$ That takes care of half the multiple hemisphere problem. The other half is arcs longer than 180 degrees. (postgis.net/docs/manual-1.5/ch04.html#id358554) $\endgroup$ Commented Apr 21, 2014 at 15:02
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1$\begingroup$ Using only two data points, how would you define an arc longer than 180 degrees? I don't think it is possible. You always have to assume (define a priori) how the two points will be joined, and the shortest segment on a Great Circle connecting the points is the only reasonable way I can think of. $\endgroup$– winwaedCommented Apr 21, 2014 at 19:08
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$\begingroup$ I was also thinking that similar to a tangent function you always have to tell the algorithm which quadrant or in this case distance you are interested in. $\endgroup$ Commented Apr 21, 2014 at 20:30
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I agree with Speissburger that PostGIS (an extension of Postgre) has excellent Geospatial support. In the open source world, this would also be my recommendation. (MySQL claims to have some geospatial support but it is very limited in capabilities)
For completeness, Microsoft's SQL Server also has good geospatial support - I think it was introduced as an extension to SQL Server 2008, and then standard after that. I have heard that Oracle also has good geospatial support, although I have never use it.
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$\begingroup$ Are you sure these can do polar searches? Or, multi-hemisphere i.e. crossing prime meridian, IDL, over a pole, over both poles? I can't find this information. Do you have a reference? $\endgroup$ Commented Apr 21, 2014 at 2:20
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$\begingroup$ I'm not sure, but I thought it was implied (unlike say MySQL where the Search cabilities are so limited, one would not expect this kind of support). I see Speissburger has updated his answer... $\endgroup$– winwaedCommented Apr 21, 2014 at 12:52