April 2018
Beginner to intermediate
440 pages
11h 36m
English
Content preview from Mastering Geospatial Analysis with Python
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Querying raster metadata
Using PostgreSQL, you can perform various queries on your data. In this section, you will learn how to query the raster for basic metadata and properties. This section will present a few of the many PostgreSQL functions that are available.
You can query the data for a basic text summary. The following code shows you how to use the ST_Summary() function:
cursor.execute("select ST_Summary(rast) from bigi;")cursor.fetchall()
The summary function takes the raster data column as a parameter and returns a string containing the size of the raster, the bounding box, the number of bands, and if there are no data values in any of the bands. The following is the output from the previous code:
[('Raster of 7x4 pixels has 1 band ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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