Database Reference
In-Depth Information
Working with basic raster information
and analysis
So far, we checked and imported the PRISM and SRTM rasters into the
chap5
schemaofthe
postgis_cookbook
database.Wewillnowproceedtoworkwiththe
rasters within the database.
Getting ready
In this recipe, we explore functions that provide insight into the raster attributes and
characteristicsfoundinthe
postgis_cookbook
database.Indoingso,wecansee
whether what is found in the database matches the information provided by
gdal-
info
.
How to do it...
PostGIS includes the
raster_columns
view to provide a high-level summary of
all the raster columns found in the database. This view is similar to the
geo-
metry_columns
and
geography_columns
views in function and form.
Let'srunthefollowingSQLqueryinthe
raster_columns
viewtoseewhatinform-
ation is available in the
prism
table:
SELECT
r_table_name,
r_raster_column,
srid,
scale_x,
scale_y,
blocksize_x,
blocksize_y,
same_alignment,
regular_blocking,
num_bands,
pixel_types,
