Could you please recommend some GIS projects with an open source (or free trial) access to the GeoTIFF data over WMTS protocol (image/tiff format in Capabilities.xml)?
There are Web Services/Cloud Providers that can stream GeoTIFF tiles over WMTS.
For example, Sentinel-Hub https://www.sentinel-hub.com/
It accepts GetTile request URL parameters:
FORMAT The returned image format.
Optional, default: "image/png", other options: "image/jpeg", "image/tiff"
Some notes on WMTS:
- WMTS is not a format, it is an OGC Standard; it is an
interfaceas defined in the official standard. Web Map Tile Service is a popular interface that can be used for serving georeferenced map tiles over the HTTP.
- WMTS does not rely on JPEG or PNG, it is just a recommendation to WMTS servers to support well-known image formats; see item 11.3 of the standard - this does not exclude supporting other image formats.
- WMTS does not restrict the set of formats in which tiles can be provided.
The GeoTIFF format was initially developed during the early 1990’s (N. Ritter & Ruth, 1997). The objective was to leverage a mature platform independent file format (TIFF) by adding metadata required for describing and using geographic image data. TIFF met the requirements for an underlying format, as it was - and still is (though JPEG compression was added) - lossless and extensible. (...)
The Web Map Tile Service (WMTS) Implementation Standard provides a standard based solution to serve digital maps using predefined image tiles. The service advertises the tiles it has available through a standardized declaration in the ServiceMetadata document common to all OGC web services. This declaration defines the tiles available in each layer (i.e. each type of content), in each graphical representation style, in each format, in each coordinate reference system, at each scale, and over each geographic fragment of the total covered area. The ServiceMetadata document also declares the communication protocols and encodings through which clients can interact with the server. Clients can interpret the ServiceMetadata document to request specific tiles. (...)
WMTS doesn't use TIFF for broadcasting map tiles, it relies on JPEG or PNG instead:
It is recommended that servers offer Tiles in the image/png and image/jpeg file formats. The image/png image format is good for categorical maps and image/jpeg is better for imagery but since image/jpeg does not support transparency, image/png may be used for images. It is recommended that WMTS Clients support both. Since a GetTile operation can serve only one tile at a time, it is important that clients have the ability to support transparency and also be able to overlap tiles from the same geographical area.
Such service may be available, e.g. for the city of Wien (AT) at: https://maps.wien.gv.at/wmts/1.0.0/WMTSCapabilities.xml or check if your local government is providing such services.
But you won't find any GeoTIFF through WMTS, by definition.