Enhance WMTSGenerator for Multi-Layer Support

[alonakos]

WMTSGenerator Multi-Layer Support

Currently, the WMTSGenerator implementation supports only a single layer per dataset. We need to include separate <Layer> elements for each statistic or data layer in the WMTS capabilities document.

Option 1: Extend the Current Class

• Changes:
  • Modify the WMTSCapabilitiesGenerator class to support multiple layers:

    self.layers = []

  • Create an add_layer() method and call it for every layer before writing the XML in the file.

    def add_layer(self, layer_title: str, layer_identifier: str, tile_format: str, url_postfix: str, bounding_box: dict = None)

  • Update the XML generation logic to iterate over self.layers and generate a <Layer> element for each.

Option 2: Use OWSLib

• Pros:

  • Ability to parse and modify the WMTS document post-generation.
  • Support for any OGC specifications updates.

• Cons:

  • Introduces an external dependency.
  • More refactoring is needed compared to the current XML handling logic (from xml.etree.ElementTree to OWSLib).