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Questions tagged [geohashing]

Geohash is a latitude/longitude encoding system using Base-32 characters.

Geohash is a latitude/longitude geocode system invented by Gustavo Niemeyer when writing the web service at geohash.org, and put into the public domain. It is a hierarchical spatial data structure which subdivides space, then interleaves the latitude and longitude information in a bitwise fashion.

Geohashes offer properties like arbitrary precision and the possibility of gradually removing characters from the end of the code to reduce its size (and gradually lose precision).

Nearby places will often (but not always) present similar prefixes. The longer a shared prefix is, the closer the two places are.

See https://en.wikipedia.org/wiki/Geohash

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Spatial data with mongodb or cassandra

I am considering a Proof of concept for handling large volumes of data like > 10 G which requires atleast 200+ writes per second and about 50+ reads per second of spatial related data. This is a growing system as well. Currently I am considering…
Muthu
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How to use Redis and geo proximity search to find two users at the same location?

I want to implement a service that, given users' geo coordinates, can detect whether two users are at the very same location in real time. In order to do this in real time and to scale, it seems I should go with a distributed in-memory datastore…
Simian
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Finding geohashes of certain length within radius from a point

I have points with a given latlong and a distance around them - e.g. { 40.6826048,-74.0288632 : 20 miles, 51.5007825,-0.1258957 : 100 miles}. If I pick a fixed geohash length (say equals to ~ 1x1mile) how can I find all the geohash entries of that…
naumcho
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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…
freakTheMighty
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geohash string length and accuracy

if length of geohash string is more, it is more accurate. But is there any direct relationship like if length is 7 it is providing 100 meter accuracy, i.e. if two geohash (and either of their bounding box) is having first 7 char matching, both…
Raxit Sheth
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Geohash Module installed but import error

I am using ipython Jupyter notebook in Windows 10. I have installed Geohash using pip install geohash in cmd. When I try to use geohash( import geohash) following error…
Himal Acharya
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How to calculate the geohash of the viewable area/bounding box?

I've recently start working on a personal project involving geo locations, maps (Google Maps V3) etc. The project is developed in Python and is intended to run on Google App Engine. I've learned that in order to find markers/position close to a…
Ken
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Python calculate lots of distances quickly

I have an input of 36,742 points which means if I wanted to calculate the lower triangle of a distance matrix (using the vincenty approximation) I would need to generate 36,742*36,741*0.5 = 1,349,974,563 distances. I want to keep the pair…
mptevsion
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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),…
itsme
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Hash function for 3d integer coordinates

Having a 3D uniform grid, in order to save memory in large models the empty cells(those that don't overlap with any object) don't need to be saved. I am using Dictionary in c# for this purpose. Although the performance already has decreased yet this…
ali
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In solr dih import two double in one location

What I have now is the two double filds: and what I want: the 2…
vuky
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Advice on pubsub topic division based on geohashes for ably websocket connection service

My question concerns the following use case: Use case actors User A: The user who sets a broadcast region and views stream with live posts. User B: The first user who sends a broadcast message from within the broadcast region set by user A.…
html_programmer
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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!
Kyle
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MongoDB: Cluster documents by geographic location given area and max points?

I'm trying to develop a map-based visualization which includes a "heat map" of subpopulations, based on a MongoDB collection that contains documents like this: { "PlaceName" : "Boston", "Location" : { "type" : "Point", …
DanM
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Sunspot Spatial Search Not Returning Results

I've just implemented the Sunspot gem into my application and I really like it except for the fact that when I do a location search it seems to be excluding some results. For example: I live in Columbus Ohio so if I search for "Columbus Ohio" my…
Kyle Decot
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