Allowing user to alter WebMapServiceCatalogItem parameters

[jiwalker-usgs]

For the map COLORSCALERANGE feature I've added a widget to change the min and max range that is placed into the parameters field on WebMapServiceCatalogItem. In changing these values I cannot determine the appropriate way to reload the CatalogItem to use the new parameters (the ImageryProvider is already setup with what appears to be a fixed parameters list). I've gotten around this by toggling the isShown property, but this has undesired effects.

@kring what would you recommend for changing the parameters and getting them to apply to GetMap and GetLegendGraphic requests when changing parameters like COLORSCALERANGE?

[kring]

@jiwalker-usgs this is a bit tricky. If you can point me to the branch with your work so far, I can add that bit and show you how I did it.

[jiwalker-usgs]

@kring I've got my changes here jiwalker-usgs/terriajs@a995577 and it works if I manually toggle the item off and on. I'm missing the programmatic way of doing this, and the legend seems to be somewhat static.

[kring]

Ok I've made the changes:
https://github.com/TerriaJS/terriajs/compare/newui...colorScaleRange?expand=1

Basically we need to do two things:

• Update the legendUrl, which will make the UI automatically display the new legend.
• disable and then re-enable the layer so that the new parameters get picked up. This is a little ugly, but it's our best option right now as Cesium doesn't support changing the parameters to a WMS after it is created. We do the same thing for time-dynamic layers.

I also changed the UI to call a refresh function that triggers these two actions when the color range changes.