Build a Geospatial App with Redis 3.2- Andrew Bass, Sean Yesmunt, Sergio Prada, Deanna Shih, Coding House

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http://bit.do/redis

We will be using this data for our presentation!

Redis 3.2 and GeospatialAndrew Bass, Deanna Shih, and Sean Yesmunt

• Students at Coding House in Fremont, CA • Andrew Bass • Deanna Shih • Sean Yesmunt • Sergio Pradapaceme.us

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Who are we?

• Stable as of May 6, 2016

• Includes a new set of GEO commands for geo indexing

• Simply put, saves locations and compares them

• Geo indexed data is a special sorted set

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Redis 3.2 and GEO

GEOADD key longitude latitude member GEOHASH key member

• Longitude then Latitude

• Assumes Earth is a sphere

• Data is saved in sorted set as a Geohash

• ZREM can can be used to remove a member from the key

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GEOADD & GEOHASH

Divide the world in half

Each half is 0 or 1

Save that bit, then keep dividing

Images from: mapzen.com/blog/geohashes-and-you/

@RedisConf 122.393 W, 37.768 N

or

0100110110010001111011110

Or, in GEOHASH9q8yyg72zpm0

Images from: mapzen.com/blog/geohashes-and-you/

Why?

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Redis can compare the locations as a sorted set!City Geohash

San Francisco 9q8yyg7zpm0

San Jose 9q9k6mjng

Los Angeles 9q5ctr186

London gcpvj0duq

Beijing wx4g0bm6c

GEOPOS key member [member ...]

• Returns Longitude and Latitude for member of a key

• Since the data is converted to a string and back, it may be slightly different than the original GEOADD inputs

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GEOPOS

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Longitude and Latitude Accuracy

https://en.wikipedia.org/wiki/Decimal_degrees

GEODIST key member1 member2 [unit]

❖ Returns the distance between two members of a key

❖ Unit is defaulted to meters, but accepts:• m for meters

• km for kilometers

• mi for miles

• ft for feet

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GEODIST

GEORADIUS key longitude latitude radius m|km|ft|mi [WITHCOORD] [WITHDIST] [WITHHASH] [COUNT count] [ASC|DESC]

• Returns members of a key within the radius from the coordinates • Options for including coordinates, distance, limit number of results,

and sort ascending or descending • Note, WITHHASH returns a 52bit integer, not the geohash.

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GEORADIUS

GEORADIUSBYMEMBER key member radius m|km|ft|mi [WITHCOORD] [WITHDIST] [WITHHASH] [COUNT count] [ASC|DESC]

• Returns members of a key within the radius of the given member • Otherwise, same as GEORADIUS

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GEORADIUSBYMEMBER

Demo AppFind people close to you who are also at

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For another demo, check out paceme.us