[spatial4j-dev] Writing shapes to WKT/GeoJSON

[Ryan McKinley <ryantxu@xxxxxxxxx>]

I am looking for a nice way to expose Shapes in an Apache Solr response writer.

I have hacked something together that will convert a Shape (JTS or otherwise) to a NamedList in a DocTransformer.  This works OK -- it is a bit ugly and not something that could generally work in Solr since it is JTS specific.  It also uses a lot more memory than necessary because creates temporary NamedList objects.

I have seen this comment:

<b>Spatial4j in the near future won't support writing shapes to strings.</b>

https://github.com/spatial4j/spatial4j/blob/master/src/main/java/com/spatial4j/core/context/SpatialContext.java#L324

Are we sure this is a good idea?   If the problem is that we do not have a consistent format (WKT vs 'x, y') can't we just pick a standard format?

Are there objections to adding 'write' functions on the Shape interface?  Maybe:

  public void writeGeoJSON(Writer writer) throws IOException;

  public void writeWKT(Writer writer) throws IOException;

Alternatively, should this be done in the SpatialContext?  If so, is there a reason we do not have:

  public SpatialContext getSpatialContext();

With some write options available, we could add out-of-the-box support for Shapes in the Solr response.  As is, we kind of require the output to be a stored text field, and have no option if the Shape is modified (clipped, whatever)

thoughts?

ryan