Thank you Greg, I will try to make sure to work some of these remarks into the GeoSPARQL review.
Happy holidays, Marco On Sun, Dec 15, 2019 at 9:47 AM Greg <galbis...@mail.com> wrote: > Hi Marco, > > Thank you for the invitation but I'm not sure I have the availability for > the meetings. I've thrown down some notes about various things that cropped > up while I was working with GeoSPARQL. Some you will already be aware from > Jena, others are minor snags and some speculative ideas. > > Thanks, > > Greg > > - getSRID replaced by getSRS or getSRS_URI as it is a URI that is returned > and not an integer as in the Simple Features standard. > - fixing error in the published XML schema: "defaultGeometry" to > "hasDefaultGeometry". > - conformance queries and dataset/s so that both functionality and > correctness can be demonstrated by implementations in a standard manner > (this is a major shortfall and some mechanism is needed). > - performance queries and dataset/s (although this is probably best left > as an area of wider research). > - inclusion of GeoJSON as an explicit serialisation property with > examples, i.e. asGeoJSON, given the widespread usage of JSON data. > - there are variations between the equals realtions of GeoSPARQL/Simple > Features standards (TFFFTFFFT) and those in use by some libraries, e.g. > JTS (T*F**FFF*), to allow equality between Points to be tested. > - aggregate functions (as included in Strabon), e.g. union and extent > across N geometries. > - convenience geometry filter functions (to simplify query syntax), e.g. > isPoint, isLineString, isPolygon, nearby points up to limit, points within > bounding box up to limit. > - geometry manipulation (as found in PostGIS functions), e.g. splitting > polygon into points or forming linestring from points, forming a linestring > from set of linestrings, transform datatype/serialisation. > - geometry functions, e.g. centre point of polygon, bounding box of > geometry, midpoint of a line, point along line by distance from start/end, > test relative positions of geometries (e.g. point is to left of line), > pathfinding? (e.g. A* across set of points). > - SRS functions, e.g. isProjected, isGeographic, and functions to > translate between SRS. > - cardinal direction functions, e.g. north, south, east, west. Would > require wrap around for geographic SRS. > - considering support for geographic SRS as WGS84 appears in most > examples. e.g. great circle distance, angle, azimuth. > - filter functions for Geometry properties but applied to Geometry > Literals. > > > On 08/12/2019 17:39, Marco Neumann wrote: > > I am still using my old GeoSPARQL implementation with the new Apache Jena > libs on the GeoSPARQL.org endpoint. I will have to find some time to > further evaluate and possibly switch over to your new GeoSPARQL module > early in the new year. > > The OGC GeoSPARQL team has invited me to participate in > the discussion about a new OGC GeoSPARQL 2.0 specification later in the > month. Will be interesting to see how the use of geospatial features will > evolve in the RDF ecosystems in 2020. If you are interested to join these > meetings please let me know. > > Best, > Marco > > > On Sun, Dec 8, 2019 at 1:30 PM Greg Albiston <galbis...@mail.com> wrote: > >> Thanks for this Marco. Interesting to see it all in action. >> >> Apache Jena GeoSPARQL does quite well. >> >> I've ran the benchmarking dataset against Jena 3.13.1 for the one query >> they said didn't give results. >> It does give results and in a couple of seconds as reported for the other >> systems so unsure what has happened there. >> >> Cheers, >> >> Greg >> On 04/12/2019 14:00, Marco Neumann wrote: >> >> FYI here is a new review / comparison that mentions the new Apache Jena >> GeoSPARQL effort in this recent publication: >> >> Assessment and Benchmarking of Spatially Enabled RDF Stores for the Next >> Generation of Spatial Data Infrastructure >> >> by Weiming Huang,Syed Amir Raza,Oleg Mirzov and Lars Harrie >> >> ISPRS Int. J. Geo-Inf. 2019, 8(7), 310; >> https://doi.org/10.3390/ijgi8070310 >> >> >> Enjoy, >> Marco >> >> -- >> >> >> --- >> Marco Neumann >> KONA >> >> > > -- > > > --- > Marco Neumann > KONA > > -- --- Marco Neumann KONA
