Open knutole opened 8 years ago
We should be already cutting the raster into pieces of 128x128 pixels at import time.
The scandinavia snow
raster cuts in 96 rows here, at full resolution.
It takes ~28 seconds on my system to dump each of those 96 rasters into 517,825 polygons and write them into a new table using a (ST_DumpAsPolygons(rast)).*
query. The time halves removing the ().*
syntax, as it is known to run the internal function once for each output field (2 fields in our case). Is that enough of an improvement ? Where's the code doing the vectorialization ?
I found two places, both using the ().*
syntax:
src/pile.js:420
src/vectorize_raster.sh
Currently the vectorize raster function (
ST_DumpAsPolygon
) is taking around 20-30 seconds to process a 1.6MB raster.It's all being done one 1 CPU. Possibly there's a way to cut this job into pieces and do them parallel, utilizing 6-8 CPU's.