Hello, -The computation of slope (in degrees) is relatively slow, taking about 20 seconds for analysis using ArcGIS Pro.
version:pg12+postgis340 --postgis_full_version POSTGIS="3.4.0 0" [EXTENSION] PGSQL="120" GEOS="3.12.0-CAPI-1.18.0" SFCGAL="SFCGAL 1.4.1, CGAL 5.4.5, BOOST 1.72.0" PRO J="8.2.1 NETWORK_ENABLED=OFF URL_ENDPOINT=https://cdn.proj.org USER_WRITABLE_DIRECTORY=/home/postgres/.local/share/proj DATABASE_PATH=/usr/local/proj-8.2.1/share/proj/proj.db" GDAL="GDAL 3.6.2, released 2023/01/02" LIBXML="2.9.11" LIBJSON=" 0.15" LIBPROTOBUF="1.4.1" WAGYU="0.5.0 (Internal)" TOPOLOGY RASTER raster2pgsql -I -s 4326 -t 32x32 "/opt/raster_data/changjiang12.tif" | psql -h localhost -p5432 -Upostgres -dpostgis340 -After importing, the TIFF file is 14MB and 12198 rows. postgis340=# \d changjiang12 Table "public.changjiang12" Column | Type | Collation | Nullable | Default --------+---------+-----------+----------+------------------------------------------- rid | integer | | not null | nextval('changjiang12_rid_seq'::regclass) rast | raster | | | Indexes: "changjiang12_pkey" PRIMARY KEY, btree (rid) "changjiang12_st_convexhull_idx" gist (st_convexhull(rast)) postgis340=# EXPLAIN ANALYSE select ST_Slope(rast) as slope from changjiang12; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------ Seq Scan on changjiang12 (cost=0.00..4894.48 rows=12198 width=32) (actual time=22.371..142759.655 rows=12198 loops=1) Planning Time: 0.836 ms Execution Time: 142764.987 ms (3 rows) Time: 142770.199 ms (02:22.770) -Where can improvements be made? Thanks.
