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Mastering PostGIS

You're reading from   Mastering PostGIS Modern ways to create, analyze, and implement spatial data

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Product type Paperback
Published in May 2017
Publisher Packt
ISBN-13 9781784391645
Length 328 pages
Edition 1st Edition
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Authors (4):
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George Silva George Silva
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George Silva
 Mikiewicz Mikiewicz
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Mikiewicz
Michal Mackiewicz Michal Mackiewicz
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Michal Mackiewicz
 Nycz Nycz
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Nycz
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Toc

Table of Contents (9) Chapters Close

1. Importing Spatial Data FREE CHAPTER 2. Spatial Data Analysis 3. Data Processing - Vector Ops 4. Data Processing - Raster Ops 5. Exporting Spatial Data 6. ETL Using Node.js 7. PostGIS – Creating Simple WebGIS Applications 8. PostGIS Topology 9. pgRouting

Chapter 4. Data Processing - Raster Ops

PostGIS raster's goal is to implement the raster type as much as possible like the geometry type is implemented in PostGIS and to offer a single set of overlay SQL functions (such as ST_Intersects) operating seamlessly on vector and raster coverages.

Each raster or raster tile is stored as a row of data in a PostgreSQL database table. It is a complex type, embedding information about the raster itself (width, height, number of bands, pixel type for each band, and no data value for each band) along with its geolocalization (pixel size, upper left pixel center, rotation, and SRID). These metadata are accessible by raster_columns view.

Something that shows flexibility of PostGIS raster support is in-db / out-db raster tile storage. Operations on these are identical, no matter if the raster is stored internally in PostgreSQL or file in filesystem. The only drawback is query processing time for out-db raster coverages.

PostGIS Raster is expressed in different...

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