Dear Bertoni,

There are three different ways to change/manipulate projections in QGIS:

1. Project Properties > CRS (or you can click on the icon where EPSG is written in the bottom right corner)

This defines the proprieties of the canvas (the background layer). For example, if I want to display a background map from the OpenLayers plugin (google street etc.) I will need to set the project CRS to EPSG:3857.

2. Right-click on vector layer > Set Layer CRS

This will force QGIS to accept the CRS that you define, whatever the metadata or previous settings might say. Essentially you are overruling whatever was there previously. If you have ended up with some data that has no CRS defined, and you know what it should be, this is the one to use. It should be noted that this does not modify the actual shapefile (unlike when you set a CRS in ArcCatalog), it only modifies the layer properties.

3. Right-click on vector layer > Save As...

Here you can set the CRS when you save your data. If you select a new CRS, this will transform the coordinates of the data to the new coordinate system and save the result in the appropriate file. Depending on what you select you will also get to specify the transformation method. This is used when you already have your data in the correct CRS, but you want to save it in a different projection.

Regards.

Thanks younso much. Yesterday I tried the soluzione n1 but the project was already on the right EPSG. Now I'm going to try the other two methods.

Dear Bertoni,

if it is possible for you to use ARCMAP, you can use these two tools:

- define projection

- project

when your layer does not have any predefined coordinate system and you want to define it, you can use the first one and if you want to change the coordinate system of a layer you can use the second one.