# Vowa Baselayers – Implementation and Maintenance

### Implementation

The QGIS plugin is implemented as standard QGIS plugin with Python. It uses tables in the schema qgis\_tools in the DPSpatial database for storing the information on the layers to be loaded into QGIS. The documentation on the tables of this schema is [on this page](https://wiki.vogelwarte.ch/books/schema-qgis-tools/page/tables-in-schema-qgis-tools "Tables in schema qgis_tools"). The QGIS plugin repository can be found [on the Vogelwarte GitLab](https://gitlab.vogelwarte.ch/scientific-it/qgis-plugins/QGIS-Plugin-basemap-perimeter).

Purpose, installation, and usage of the plugin are documented [on this page](https://wiki.vogelwarte.ch/books/qgis/page/vowa-baselayers-purpose-installation-usage).

### Layer Types

The following layer types can be provided through the QGIS plugin:

- WMS
- WMTS
- QGIS Layer File
- Shapefile
- GeoPackage
- GeoTIFF
- PostGIS Vector Layer

Each layer type requires a set of parameters so that it is loaded properly in QGIS. You find the specification [on this page](https://wiki.vogelwarte.ch/books/schema-qgis-tools/page/tables-in-schema-qgis-tools).

### Test Layers

In order to add layers in the table vowabaselayers that are only visible for development and test users you have to do the following:

1. Create the environment variable "VOWA\_BASELAYERS\_DEV=true" on your computer.
2. Add the layers and give them IDs greater than 1000.

### &-Character in Tab Titles

The QGIS plugin replaces '&' characters in tab titles by default with '\_'. If you want to use the '&' character in tab titles type it twice. For instance, the tab title "Lakes && Rivers" will be shown as "Lakes & Rivers" in the QGIS plugin.