David, Thank you for the response. I did indeed stumble upon an example using Lucene 4.x and used it only because that is what I’ve found, I see now that there are examples in lucene-solr 5.x and 6.x. After your response I did some more research and see all of the work that’s been done on spatial searches in 5x and 6.x. I think I’ll try to use 6.0.1 and then move to 6.1 when it comes out.
I now see that after the Lucene API “query filter merger” the newer examples use query searches and no filters. With LatLonPoint.newPolygonQuery() it looks like I don’t need Spatial4j at all any more either. This makes my case very simple, I only have to index LatLonPoint’s and then do a query search with LatLonPoint.newPolygonQuery(). I see that it still depends on JTS. By the way while researching this I happened to Google up the talk that you recently gave at Harvard CGA, thanks for that, very timely for what I’m working on! Thanks again for your help - Randy > On Jun 6, 2016, at 1:01 AM, David Smiley <david.w.smi...@gmail.com> wrote: > > Hello Randy. > > If you are on Lucene 6x, or possibly some late 5x releases, there are newer > Lucene spatial implementations that have fewer moving parts to them and so > will be simpler. I'm almost certain they would be fastest too, although > perhaps that's not much of an issue with only 100k's of data points. See > LatLonPoint in the "sandbox" module, which will likely graduate to > "spatial" for v6.1. In particular see the newPolygonQuery method. > > To stay within the SpatialStrategy API (in 6x this is in the > "spatial-extras" module, in 4x and 5x it was simply the "spatial" module), > you would approach this like so: > > Use an instance of JtsSpatialContextFactory.GEO or construct an instance if > you wish to customize settings. This is called the "spatial context", > often in a variable of "ctx". If you reference the latest Spatial4j 0.6 > then you can call ctx.getShapeFactory().polygon() which is a builder for a > polygon -- I'm sure you'll figure it out. > https://github.com/locationtech/spatial4j/blob/master/src/main/java/org/locationtech/spatial4j/shape/ShapeFactory.java > This is for building a shape manually / programatically. If instead you > have GeoJSON or WKT then you will find readers for them from the context. > SpatialArgsParser is another option but I suggest avoiding it. Spatial4j > 0.6 will definitely work with Lucene 6x, very likely with 5x, somewhat > likely with 4x. > > Now you have an instance of a Shape and you can see in the > SpatialExample.java you referenced how to search by a shape. For example > in the filter-by-circle example, swap out the ctx.makeCircle reference with > your newly constructed polygon shape instance. Otherwise that's it. It's > not clear if you happened upon that example in the 4x branch but are > unaware it exists in 5x & 6x or wether you deliberately referenced 4x > because you must use that version. > > Good luck, > > ~ David > > On Sat, Jun 4, 2016 at 12:34 PM Randall Tidd <r...@tidd.cc> wrote: > >> Hello, >> >> I have what I think is a relatively simple use case that I’d like to use >> Lucene to solve. We have a database of 100,000’s of data points each of >> which has a latitude and longitude. I’d like to index these and then be >> able to search for them with an arbitrary polygon. For example I would >> define an irregular polygon roughly encompassing northern San Francisco and >> search for all points that are within that polygon. >> >> I see some examples that are close to what I need but have some >> questions. For example there is this: >> >> >> https://github.com/apache/lucene-solr/blob/branch_4x/lucene/spatial/src/test/org/apache/lucene/spatial/SpatialExample.java >> < >> https://github.com/apache/lucene-solr/blob/branch_4x/lucene/spatial/src/test/org/apache/lucene/spatial/SpatialExample.java >>> >> >> But 1) this is based on Lucene 4.x while the latest version is 6.x, and 2) >> it searches for points within a circle, not a polygon. >> >> I would be happy to use Lucene 4.x if that provides the best support but >> that version is getting old now and I wonder if there is better, easier >> support in later versions. >> >> Doing some reading I see that Spatial4j and JTS provide support for >> polygons, but I can’t figure out how to define a polygon that can be used >> with SpatialArgs. I found >> com.vividsolutions.jts.geom.GeometryFactory.createPolygon() but am not sure >> how to get that into a JTS Shape which can be used with SpatialArgs. >> Basically I’m getting lost in the 3 sets of API’s (Lucene, Spatial4j, and >> JTS) wondering how they go together and can’t find an example. >> >> I have also tried parsing arguments to create a polygon like this: >> >> SpatialArgs args = new >> SpatialArgsParser().parse("IsWithin(POLYGON-122.515193 37.781561, >> -122.472924 37.809958, -122.383509 37.808795))", ctx); >> >> But I get "java.text.ParseException: Unknown Shape definition” from >> com.spatial4j.core.io.WKTReader.parse, evidently it is not correctly >> using JTS to create the polygon. JTS is on my class path so I’m not sure >> what is wrong there. >> >> I see mention of some Solr and ElasticSearch solutions, which I believe >> would just use this Lucene functionality underneath. I’d be happy to use >> those if it were easier but seems like I should be able to do this with >> just Lucene. >> >> Here is the combination of toolkits I’m trying to use: >> >> compile group: 'org.apache.lucene', name: 'lucene-core', version: '4.10.4' >> compile group: 'org.apache.lucene', name: 'lucene-analyzers-common', >> version: '4.10.4' >> compile group: 'org.apache.lucene', name: 'lucene-spatial', version: >> '4.10.4' >> compile group: 'com.spatial4j', name: 'spatial4j', version: '0.5' >> compile group: 'com.vividsolutions', name: 'jts', version: ‘1.13' >> >> I’ve spent more time figuring this out than I thought I’d have to and >> think I must be missing something obvious, and am wondering if someone can >> help me out. >> >> Thanks, >> Randy >> >> -- > Lucene/Solr Search Committer, Consultant, Developer, Author, Speaker > LinkedIn: http://linkedin.com/in/davidwsmiley | Book: > http://www.solrenterprisesearchserver.com --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
