[New Feature]: Mapped Style/Symbologies

[tariqksoliman]

Checked for duplicates

Yes - I've already checked

Alternatives considered

Yes - and alternatives don't suffice

Related problems

No response

Describe the feature request

Currently

Right now, the only way to custom style each feature in a vector layer, with say a fill color, is to include that color itself somewhere within each feature's properties object. This means that if ever we want to restyle that feature, we'd have to update that field in the geojson itself.

Task

Often such color field is derived from other fields within the metadata. This ticket is to add support for configuring a value-to-color mapping for vector layers.

Sample use case

For instance, I might have a field called direction that is a integer that goes from 0 to 360. This new feature would enable me to, through the /configure page, state that geojson features shall be styled blue if direction is 0 and gradiently red as direction approaches 360.

How styles are currently applied

Vector layers are styled in the constructVectorLayer function.

The priority of stylings is defined in https://nasa-ammos.github.io/MMGIS/configure/formats/vector-styling. Roughly speaking:

• properties.style.* fields take priority
• followed by the configured "From Property" fields in the Style Tab
• followed by the color-pickers/slider values in the Style Tab
• followed by some default

One idea

One idea to incorporate style mappings into /configure is to include it into the Legend Tab.

The Legend Tab entries would each get four new components:

• A text input for property name
• A text input for property value
• A checkbox for style matching feature according to this
• A checkbox for hide this item from the legend

Notes

• Ideally the style mapping works across integer, floating point, boolean, and string fields.