QGIS – Setting a Default Map Projection

by David Crowther

Question:

In QGIS is it possible to set my default Map projection?

Answer:

Yes, QGIS has a number of default options that you can apply to define the Projections for your Projects and Layers.

Project CRS –

To define the default Coordinate Reference System (CRS) used for new QGIS Projects, choose Settings > Options > on the CRS Tab > and the CRS for Projects section you can choose the Default Projection used when a new Project is created.

Now when you choose to create a New Project you will see that the default CRS has been set to British National Grid (27700).

New Layer CRS –

To define the default Coordinate Reference System (CRS) used for newly created Layers, or for those that have no CRS choose Settings > Options > on the CRS Tab > and the CRS for Layers section you can choose the Default CRS for Layers and then tick the radio button labelled – Use default layer CRS.

Now when you choose to create a New Layer (or add one without a CRS) you will see that the default CRS has been set to British National Grid (27700).

Datum Transformation –

To define how QGIS calculates transformation from one CRS to another, choose Settings > Options > on the CRS Tab > and the Default Datum Transformations section you can choose to add, remove and configure your own options for defining the transformation process that a source layer will use to then be rendered in a QGIS map with another projection set.

If several different options are available you can choose to ask the user which Transformation option they would prefer?

You may wish to resolve those Datum Transformation queries for your users by defining just one option and removing the need for the user to keep choosing.