Uniform configuration & definition of maps across mobile and web

[ekigamba]

As per this #178 (comment) by @mberg

I don't want to create to much extra work but it would be great if we could reference a seperate json file (mapviz spec) to to define the properties of the style spec. It would be really nice to be able to have a style spec that can be replicated across android and mobile. I realize for our use case it will be pretty simple to configure this manually but I thinking having this as a config file would be really awesome.

Can you connect with @cKellyDesign to understand how gisida works and let us know if you think it's feasible? Again, this is not a priority if time is an issue but would be good to support longer term.

A discussion with the Gisida team(@cKellyDesign and @KipSigei) about this is required probably with guidance from @mberg on the original idea and expected outcome based on future project expectations