The Layer Exchanger interface is used to export  a TerraLib layer to a external data source.  It is also possible to reproject it  to another projection defined in SRID parameter.

The list of output data source types may vary depending on the plugins loaded (PostGIS, Vector (OGR), Raster (GDAL).

It is accessible through:

    Layer Explorer >  Right Clicking over a Layer-name > Exchange... (used to export a specific layer)

or

    Tools > Data Exchanger > Layer Exchanger... (all layers are listed and one must be selected)

To export a layer, the following steps are required:

1. Select the Input Layer .

2. Select the Output Data Source Type (DBMS: PostGIS,  Vector or Raster ).

3. Define the Output Data Source 

• For Vector  or Raster, click on   and choose the path location and the new Data Set Name.

• For PostGIS, choose one of the connections from the drop down list. 

• If the list is empty, click on  to set the database connection parameters to a known datasource (server@datasource-name@user)  using option   at the interface

• or to create a new/empty datasource  where the data will be added (using option   at the interface) 

    4. Output Dataset SRID: the default SRID is the same of the input layer. Choose a different SRID if you want to reproject the input layer .

    5. Create Spatial Index:  It is only available if the data source type supports index creation.

    5. Click on OK to export the layer.

At the end of the process a successful message or an error message will be displayed.

Error message example: 'Geometry type (Multipolygon) does not match column type (Polygon)'.

In case of ERROR MESSAGE related with geometry type,  go to the Vector Processing menu and use Check geometry option and  Make it valid option to check/correct invalid  geometries before any other vector operation.

NOTE: some SRID´s are note recognized by PostGIS (are considered as User Defined).  Choose a valid SRID in this case, and a reprojection will take place. The message below will be displayed when the SRID is not recognized by PostGIS:

"PostGIS doens't recognize this projection. Please, reproject your data to a correct one. Or save your result as Vector File, and afterwards use Exchange to put the result in PGIS, changing the USER SRID to a valid one."