Configuring TiTiler Requests

The DataHub hosts different types of data, and the TiTiler endpoint you use depends on the data format:

• Cloud Optimised GeoTIFFs (COGs): For single-band or multi-band raster data in .tif format. These requests use the /core/cog/ endpoint. This is the most common endpoint for visualising individual image files.
• Multidimensional Data (NetCDF, Zarr, Kerchunk): For data with more than two dimensions (eg. time, depth). These requests use the /xarray/ endpoint.

(Note: While a /stac/ endpoint exists for interacting with STAC Items directly, for clear and direct visualisation, we recommend using the asset URL within the /cog/ or /xarray/ endpoints as shown in the examples below.)

Band/Variable Selection (bidx / variable):

• &bidx=... for COGs (e.g. &bidx=1 for the first band).
• &variable=... for xarray data (e.g. &variable=analysed_sst).

Rescaling (rescale):

• &rescale=MIN,MAX improves contrast by mapping the data's raw values (e.g. temperature) to the full colour range.

Colourmap (colormap_name):

• &colormap_name=... applies a colour palette (e.g inferno). This is ideal for single-band data.

This URL visualises the analysed_sst variable, rescales the data to a specific temperature range (271K to 305K), and applies the inferno colourmap.

Software like QGIS often requires multiple bands to render a colour image. While colormap_name is great for single bands, it is not suitable for creating true-colour (RGB) composites. For this, you must use bidx to select multiple bands and color_formula to style them.

Options:‎‎‎

Band Selection (bidx):

• Select the bands you want to map to Red, Green, and Blue. For Sentinel-2, the true-colour bands are Red (B4), Green (B3), and Blue (B2). You must specify them in order: &bidx=4&bidx=3&bidx=2.

Colour Formula (color_formula):

• This is a powerful parameter that applies colour correction algorithms to enhance the image. A good general-purpose formula is Gamma RGB [value] Saturation [value] Sigmoidal RGB [contrast] [brightness].
• The formula helps to brighten the image and increase contrast, which is often necessary for raw satellite data.

This URL creates a visually enhanced, true-colour composite from a Sentinel-2 scene. It selects the Red, Green, and Blue bands and applies a gamma, saturation, and sigmoidal contrast stretch. This type of URL is robust for use in QGIS as an "XYZ Tile" layer. (Note: %20 is the URL-encoded version of a space character.)

For more integration with desktop GIS, you can provide a WMTS Capabilities XML document. This allows QGIS to understand the layer, its projection and available parameters.

You can construct a WMTS URL by taking a tile URL and changing the path to /WebMercatorQuad/WMTSCapabilities.xml. This URL will generate an XML file that you can load directly into QGIS as a WMTS layer. It contains the same multi-band selection and colour formula as the tile example above