geohashing

avoiding geocode range collisions

I am in the process of extracting location entities ('Madison Square Garden', 'San Diego Zoo', etc.) from a large table of non-uniform location. I'm trying to avoid multiple entities in my new table. I don't have reliable street addresses, but am trying to extract addresses within a local range. I am doing this by counting and matchin...

Google App Engine Geohashing

I am writing a web application using GWT and App Engine. My application will need to post and query items based on their latitude, longitude. As a result of google's distributed database design you can't simple query a set of inequalities. Instead they suggest doing geohashing. The method is described on this page. http://code.goo...

Geohashing format

Is there any specific format for a geohash value? Can I use Geohash.encode(latitude,longitude,precision="8") in ruby script? What is the maximum value that precision attribute can take? Thanks in advance for any help. ...

App Engine - Precomputing bounding boxes for proximity search

I'm trying to do a location-based search on App Engine, but since the data store doesn't support multiple inequality operators, I can't search "where lat between a and b and lon between c and d". One of the solutions is to pre-compute bounding boxes to search on, as explained here: http://code.google.com/appengine/articles/geosearch.ht...

Geohashing - recursively find neighbors of neighbors

I am now looking for an elegant algorithm to recursively find neighbors of neighbors with the geohashing algorithm (http://www.geohash.org). Basically take a central geohash, and then get the first 'ring' of same-size hashes around it (8 elements), then, in the next step, get the next ring around the first etc. etc. Have you heard of an ...

Use GIS to get geographic info for a single point

I am not quite sure where to start with this. I only just started looking into this in the past week, but hopefully someone can help point me in the right direction. The goal of my project is to be able to take a geohash, decode it to latitude and longitude, check the point against some GIS data, and find out some information about that...

Python GeoModel alternative

I'm looking for an alternative library for the app engine datastore that will do nearest-n or boxed geo-queries, currently i'm using GeoModel 0.2 and it runs quite slow ( > 1.5s in some cases). Does anyone have any suggestions? Thanks! ...