From e90f1d4b432016a050e02518bac4aefdab7c12f2 Mon Sep 17 00:00:00 2001 From: Mike Barry Date: Fri, 22 Oct 2021 05:30:49 -0400 Subject: [PATCH] clarify grouping/joining --- README.md | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/README.md b/README.md index 3e52c7bc..8762342b 100644 --- a/README.md +++ b/README.md @@ -145,9 +145,11 @@ download regularly-updated tilesets. ## Limitations -- It is harder to join and group data than when using database. To join input data sources, profiles must explicitly - store data when processing a feature to use with later features, or apply post-processing to rendered features - immediately before emitting the vector tile. +- It is harder to join and group data than when using database. Flatmap automatically groups features into tiles, so you + can easily post-process nearby features in the same tile before emitting, but if you want to group or join across + features in different tiles, then you must explicitly store data when processing a feature to use with later features + or store features and defer processing until an input source is + finished ([boundary layer example](https://github.com/onthegomap/flatmap/blob/b364066134c4b47184ccc60323c70bf2c0740e15/flatmap-basemap/src/main/java/com/onthegomap/flatmap/basemap/layers/Boundary.java#L294)) - Flatmap only does full imports from `.osm.pbf` snapshots, there is no way to incorporate real-time updates. ## Roadmap