This adds support for the Multidatastream entity type, as
implemented in the SensorThings version 1.1 "MultiDatastream extension"
While the specification mandates that MultiDatastreams have an
optional polygon geometry, I've encountered numerous servers
which expose different geometry types for this entity or which
return errors when attempting to read the geometries from
MultiDatastreams. Accordingly we always expose an option to
load MultiDatastreams as geometryless layers alongside the
default option to load them as polygon layers, to handle a
wider range of connections.
This mode can be used when each band in the raster layer is associated
with a fixed time range, eg. NetCDF files.
The user can either manually populate a table with begin/end dates for
each band in the raster, or build the table using QGIS expressions
which return datetime values.
Populates the expression builders with the raster bands, so that
the preview control allows users to scroll through bands and
see the expression results for each.
In this mode, the widget will call a callback function to generate
a new QgsExpressionContext as the previewed object changes. This
can be used to provide custom preview values for different objects
(i.e. for objects which aren't vector layer features), such as raster
bands or other custom objects.
In this mode, the user can specify a QGIS expression for the
lower and upper value corresponding to raster bands, using
variables like @band, @band_name and @band_description.
E.g
@band * 100
Can be used when each band represents a 100 m vertical slice
of data.
The expression will be evaluated when required to determine
the actual elevation range corresponding to each band.
This differs from the existing "Fixed Elevation Range Per Band"
mode in that "Fixed Elevation Range Per Band" requires users
to manually enter an elevation for each band separately,
and these values are then treated as constants. That mode works
best for rasters with non-regular steps in the band
elevation values, while this new mode is better for regular
band elevation steps
Use the processing context's ellipsoid instead of a hardcoded
WGS84 ellipsoid for distance calculations during network
analysis, so that the lengths used will exactly match other
measurement tools used on the same features in the same
project.
This is exposed as a user editable table of raster bands with
lower and upper values. Users can either populate the lower
and upper values manually, or use an expression to auto fill
all band values based on a qgis expression.
The expression based fill allows for users to design expressions
which extract useful information from band names, eg extracting
the depth value from a "Band 001: depth=-5500 (meters)" style
band name.
In this mode, each band in the raster can have a fixed elevation
range associated with it. This is designed for data sources which
expose elevation related data in bands, eg netcdf files, such
as a raster with temperate data at different ocean depths.
