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