Book Image

QGIS Blueprints

By : Ben Mearns
Book Image

QGIS Blueprints

By: Ben Mearns

Overview of this book

Table of Contents (14 chapters)
QGIS Blueprints
About the Author
About the Reviewers

Vector data – Extract, Transform, and Load

Our suitability analysis uses map algebra and criteria grids to give us a single value for the suitability for some activity in every place. This requires that the data be expressed in the raster (grid) format. So, let's perform the other necessary ETL steps and then convert our vector data to raster.

We will perform the following actions:

  • Ensure that our data has identical spatial reference systems. For example, we may be using a layer of the roads maintained by the state department of transportation and a layer of land use maintained by the department of natural resources. These layers must have identical spatial reference systems or be transformed to have identical systems.

  • Extract geographic objects according to their classes as defined in some attribute table field if we want to operate on them while they're still in the vector form.

  • If no further analysis is necessary, convert to raster.

Loading data and establishing the CRS conformity

It is important...