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Practical GIS

You're reading from   Practical GIS Learn novice to advanced topics such as QGIS, Spatial data analysis, and more

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Product type Paperback
Published in Jun 2017
Publisher Packt
ISBN-13 9781787123328
Length 428 pages
Edition 1st Edition
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Author (1):
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G√°bor Farkas G√°bor Farkas
Author Profile Icon G√°bor Farkas
G√°bor Farkas
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Table of Contents (15) Chapters Close

Preface 1. Setting Up Your Environment FREE CHAPTER 2. Accessing GIS Data With QGIS 3. Using Vector Data Effectively 4. Creating Digital Maps 5. Exporting Your Data 6. Feeding a PostGIS Database 7. A PostGIS Overview 8. Spatial Analysis in QGIS 9. Spatial Analysis on Steroids - Using PostGIS 10. A Typical GIS Problem 11. Showcasing Your Data 12. Styling Your Data in GeoServer 13. Creating a Web Map Appendix

Modifying the attribute table

We can not only use the attribute tables of layers, but we can also extend, decrease, or modify them. These are very useful functions for maintaining a layer. For example, as data often comes in a general format with a lot of obsolete attributes, which is practically useless for our analysis, we can get rid of it in a matter of clicks. The size of the attribute table always has an impact on performance; therefore, it is beneficial to not store superfluous data.

Removing columns

In the first example, let's delete some values from our administrative boundaries layer. If we inspect its attribute table, we can see some unnecessary columns. In my table, ID_0 and CCN_1 have constant values, which have...

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