4 ms·

Tile38 – Realtime geofencing and geospatial index, v1.11.0

126 points by tidwall 9y ago

ldng 9y ago
Inevitably this will be compared to PostGIS so maybe you could put a paragraph in the README on how it compares to it what is the usecase where Tile38 would serve you better. I must admit I don't see one for my own needs.
johneth 9y ago
This looks really useful. I've been using a similar geometry library 'S2'[1], by Google. It's mainly used for fast spatial indexing and comparison functionality, albeit more 'approximate'[2] than Tile38 seems to be. [1] http://s2geometry.io/ http://s2geometry.io/ [2] Approximate = not absolutely exact shapes when geofencing, for example.
- tidwall 9y ago
  I believe indexing with S2 can be made absolute if a polygon's boundary coverage cells contain a slice of the original shape. It's a bit more expensive on memory and insert times. But very fast and accurate queries. I've been experimenting with this method.
  - gfrangakis 9y ago
    S2 can also output interior coverings, which will return only the cells in a covering that are fully contained in a polygon. So if you encounter a point (or any cell) whose parent is in an interior covering, you don't have to do any additional checks to produce an exact result (whereas on the boundary, you may want to do a point-in-polygon test to be exact).
    - tidwall 9y ago
      Right! I forgot to mention that. You can totally skip the entire point-in-polygon for interior cells. So good.
billylindeman 9y ago
I've been following tile38 on github for quite awhile and it looks pretty awesome, but I haven't had a chance to build anything with it. Has anyone here built any user-facing applications on top of it?
- allan_s 9y ago
  shameless plug at https://www.weenect.com https://www.weenect.com we're currently experimenting with it in order to replace our mongodb, I think I will go with this and a mix of postgresql for historical data. the realtime geofencing capabilities will be a very good plus for us, as that's one of the main feature of our products, i.e being able to know when your cats or dog is going too far.
  - billylindeman 9y ago
    very cool! I built a small gsm/gps tracker for my motorcycle a few years ago. Its an interesting space.
- larsvegas_ 9y ago
  I had been following tidwall/tile38 for a while already, too without a clear use case for actually using it. When we refactored a main part of our code base the use case finally arose;-) At this point we're about to release tile38 to our staging environment. We opted for it basically for its capability to cache and spatially query geojson directly. Plus this can be done without the serialisation/deserialisation overhead. Another advantage for us is the ability to use the python-redis bindings. This let's us execute commands like this to retrieve data for a tile x,y,z request: res = client.execute_command( "INTERSECTS", our_key, "WHERE", "minzval", 1, z, "LIMIT", LIMIT, "TILE", x, y, z ) Very straightforward and very fast.
- petre 9y ago
  It's nice but it's kind of limited to simple apps. No polygon or geocorridor points of interest and you'd need a database anyway to store historic data. For anything more complex tgan point on map apps, I'd use PostgreSQL + PostGIS.
guessmyname 9y ago
Some people may not read the link because it appears grayed out in some browsers (the link has been posted before and so it appears in the browser history as visited). Maybe it's better to link to the changelog page, since this was reposted because a new version has been released [1]. [1] https://github.com/tidwall/tile38/releases/tag/1.11.0 https://github.com/tidwall/tile38/releases/tag/1.11.0
cwt137 9y ago
Is this built on top of Redis, or just use a Redis-like protocol?
- tidwall 9y ago
  It just uses the protocol.
tidwall 9y ago
To anyone coming here wondering WTF is Tile38? First I'll tell you what it's not. It's not a replacement for PostGIS, and it's not built on top of Redis. In my opinion PostGIS is the Swiss Army Knife of spatial data management. It's awesome! Especially for large datasets and complex queries. I use it all the time. Tile38 uses the Redis protocol for network transport. There're some commands that loosely resemble Redis like SET and GET, but it's otherwise a completely different project. I originally forked Redis and built the functionality on top of the C codebase. https://github.com/tidwall/redis-gis https://github.com/tidwall/redis-gis, but scrapped that project. What Tile38 is good for is very dynamic datasets where the application needs fast and simple point-in-polygon queries and streaming geofence notifications. Like vehicle pickup services, bus route services, proximity social apps, etc.

126 points by tidwall 9y ago

ldng 9y ago

Inevitably this will be compared to PostGIS so maybe you could put a paragraph in the README on how it compares to it what is the usecase where Tile38 would serve you better. I must admit I don't see one for my own needs.

johneth 9y ago

This looks really useful. I've been using a similar geometry library 'S2'[1], by Google. It's mainly used for fast spatial indexing and comparison functionality, albeit more 'approximate'[2] than Tile38 seems to be. [1] http://s2geometry.io/ http://s2geometry.io/ [2] Approximate = not absolutely exact shapes when geofencing, for example.

tidwall 9y ago
I believe indexing with S2 can be made absolute if a polygon's boundary coverage cells contain a slice of the original shape. It's a bit more expensive on memory and insert times. But very fast and accurate queries. I've been experimenting with this method.
- gfrangakis 9y ago
  S2 can also output interior coverings, which will return only the cells in a covering that are fully contained in a polygon. So if you encounter a point (or any cell) whose parent is in an interior covering, you don't have to do any additional checks to produce an exact result (whereas on the boundary, you may want to do a point-in-polygon test to be exact).
  - tidwall 9y ago
    Right! I forgot to mention that. You can totally skip the entire point-in-polygon for interior cells. So good.

billylindeman 9y ago

I've been following tile38 on github for quite awhile and it looks pretty awesome, but I haven't had a chance to build anything with it. Has anyone here built any user-facing applications on top of it?

allan_s 9y ago
shameless plug at https://www.weenect.com https://www.weenect.com we're currently experimenting with it in order to replace our mongodb, I think I will go with this and a mix of postgresql for historical data. the realtime geofencing capabilities will be a very good plus for us, as that's one of the main feature of our products, i.e being able to know when your cats or dog is going too far.
- billylindeman 9y ago
  very cool! I built a small gsm/gps tracker for my motorcycle a few years ago. Its an interesting space.
larsvegas_ 9y ago
I had been following tidwall/tile38 for a while already, too without a clear use case for actually using it. When we refactored a main part of our code base the use case finally arose;-) At this point we're about to release tile38 to our staging environment. We opted for it basically for its capability to cache and spatially query geojson directly. Plus this can be done without the serialisation/deserialisation overhead. Another advantage for us is the ability to use the python-redis bindings. This let's us execute commands like this to retrieve data for a tile x,y,z request: res = client.execute_command( "INTERSECTS", our_key, "WHERE", "minzval", 1, z, "LIMIT", LIMIT, "TILE", x, y, z ) Very straightforward and very fast.
petre 9y ago
It's nice but it's kind of limited to simple apps. No polygon or geocorridor points of interest and you'd need a database anyway to store historic data. For anything more complex tgan point on map apps, I'd use PostgreSQL + PostGIS.

guessmyname 9y ago

Some people may not read the link because it appears grayed out in some browsers (the link has been posted before and so it appears in the browser history as visited). Maybe it's better to link to the changelog page, since this was reposted because a new version has been released [1]. [1] https://github.com/tidwall/tile38/releases/tag/1.11.0 https://github.com/tidwall/tile38/releases/tag/1.11.0

cwt137 9y ago

Is this built on top of Redis, or just use a Redis-like protocol?

tidwall 9y ago
It just uses the protocol.

tidwall 9y ago

To anyone coming here wondering WTF is Tile38? First I'll tell you what it's not. It's not a replacement for PostGIS, and it's not built on top of Redis. In my opinion PostGIS is the Swiss Army Knife of spatial data management. It's awesome! Especially for large datasets and complex queries. I use it all the time. Tile38 uses the Redis protocol for network transport. There're some commands that loosely resemble Redis like SET and GET, but it's otherwise a completely different project. I originally forked Redis and built the functionality on top of the C codebase. https://github.com/tidwall/redis-gis https://github.com/tidwall/redis-gis, but scrapped that project. What Tile38 is good for is very dynamic datasets where the application needs fast and simple point-in-polygon queries and streaming geofence notifications. Like vehicle pickup services, bus route services, proximity social apps, etc.