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tweak the sketch of how painters algo works

Dane Springmeyer 2013-09-24 10:23:52 -07:00
parent ba92c9b1b6
commit 2f62465fff
1 changed files with 5 additions and 4 deletions
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9
Postgis-async.md

@ -7,10 +7,11 @@ Mapnik uses the painter's algorithm to render maps. It means that layers are dra
```
For each layer
Query the features from the layer
Wait for the features...
For each feature in this layer
Draw the feature
For each style attached to the layer
Query the features from the layer
Wait for the features...
For each feature in this layer for given style
For each matching rule draw the feature
```
In this case, the renderer spends a lot of time waiting for PostGIS to perform the query that will feed with features.