Using two inequalities in AppEngine query

Question

Possible Duplicate:
Google App Engine Geohashing

I'm trying to use AppEngine to store a model with Latitude and Longitude parameters. All seems to go alright, except when I try to retrieve all users between two locations. I do as follows:

 String query = "select from " + TUser.class.getName();
 query += " WHERE ( iLatitude >= " + lat_min + " && iLatitude <= " + lat_max + ")";
 query += " && ( iLongitude >= " + lon_min + " && iLongitude <= " + lon_max + ")";
 List<TUser> obj = (List<TUser>)pm.newQuery(query).execute();

But, as said in AppEngine Documentation, this throws a:

 java.lang.IllegalArgumentException: Only one inequality filter per query is supported.  Encountered both latitude and longitude

I'm trying to find a workarround for this, but no luck. Working with coordinates will always need at least two inequalities. How can this be solved then? Any solution? Or does anyone knows when will be implemented in AppEngine?

As the database has hundreds of thousands users, I can't filter the query just by latitude, and then iterate the result with a FOR to get the ones with the correct longitude. Too much data.

Thanks,

@dragonx notice that he didn't ask about geohashing (probably because he don't know about it). — Shay Erlichmen, Jan 02 '13 at 14:44
yeah, but if he looks at the answer to the duplicate, it's all there. — dragonx, Jan 02 '13 at 15:00

score 0 · Answer 1 · answered Jan 02 '13 at 14:42

0

You need to look into geohash which encodes tiles into a single string.
Check this blog to get an idea how to use it.

answered Jan 02 '13 at 14:42

Shay Erlichmen

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Using two inequalities in AppEngine query

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