[geomesa-users] Querying Using Geometries

[Nathan Mercer <nmercer@xxxxxxxxxxxx>]

First I should mention that I am a newbie. Just trying to get started with GeoMesa. So hopefully what I am asking is not trivial.

 

I am having trouble querying based on Geometries with FilterFactory. I am using the NaturalEarth country shapefile ingested into Geomesa. I am easily able to query based on attributes such as getting back all country features with population between two values.

 

I have successfully used the bbox filter because its interface is bbox(String propertyName, double minx, double miny, double maxx, double maxy, String srs) which as you can see does not contain any geometry, simply double values for the bounding box edges.

However, when I try to use for example dwithin instead of bbox I get errors. Its interface is dwithin(String propertyName, Geometry geometry, double distance, String units) which you can see takes a Geometry as the second parameter. This is a org.opengis.geometry geometry btw.

 

I am trying to get all country features which are 1000km from a point with latitude 48.99 and longitude -118.0 (should be Canada and United States).

My code is as follows:

 

GeometryBuilder builder = new GeometryBuilder(DefaultGeographicCRS.WGS84);

DirectPosition pos = builder.getPositionFactory().createDirectPosition(new double[]{-118.0, 48.99});

Point pnt = builder.getPrimitiveFactory().createPoint(pos);

FilterFactory ff = CommonFactoryFinder.getFilterFactory();

Filter f = ff.dwithin(CountryFeature.Attribute.the_geom.getName(), pnt, 1000.0, "kilometers");

Query q = new Query(“country”, f);

FeatureCollection results = featureStore.getFeatures(q);

 

Of course there is other code to set up CountryFeature and the featureStore, but hopefully that code is not necessary to figure out the issue.

 

The problem is that when I run this I get the following error message:

Exception in thread "main" java.lang.ClassCastException: org.geotools.geometry.iso.primitive.PointImpl cannot be cast to com.vividsolutions.jts.geom.Geometry

 

It is happening on the last line of the code above. It appears like it wants a JTS geometry, but dwithin requires an OpenGIS geometry.

 

I am successfully able to change the query to the following and it works:

Query q = new Query(“country”, CQL.toFilter("DWITHIN(the_geom, POINT(-118.0 48.99), 1000.0, kilometers)"));

 

However I prefer not to use the CQL format because I then need to build strings from the values. Also, it means I cannot take advantage of the filtering capabilities found in the FilterFactory and FilterFactory2.

 

Anybody have ideas on how to get this to work?

 

If need be, I can send the rest of the code.

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