[Potlatch-dev] P2, snapshot-server, imports, vector layers and more

[Richard Fairhurst]

Paul Norman wrote:
> Background: P2 has excellent support for data layers but their full power is
> not exposed to the user by default. I am contemplating using snapshot-server
> with some extremely large datasets to make the data available to people
> using P2 and JOSM as vector layers.

Great stuff.

> [...]
> I must admit I have not verified if this would require changes to P2. It's
> possible that P2 would work fine if snapshot-server returned negative IDs.

I've not tested it but I'm 99% sure it would. Happy to test if you set 
up an instance somewhere which serves negative ids!

> 2. Data layer exposure. To add a snapshot-server data layer to P2 you have
> to deploy your own P2 instance. This severely limits exposure. What makes it
> worse is that if I offer a data layer and deploy P2 and someone else does
> the same, you can't use both at the same time.
>
> A way to add a snapshot-server layer by pointing it at a configuration file
> (e.g. a json file) would be very useful.
>
> Better yet would also be a way to reveal data layers like imagery layers
> are, based on bbox (or better yet, by polygon).

Ok. You can already specify bboxes in vectors.xml in the same way that 
you do in imagery.xml. So I guess the problems to address are:

1. Make it easier for 'data providers' to make users aware of data layers
2. Provide easy UI for users to select data layers

For 1; we could continue with vectors.xml, and also provide a way to 
provide a URL in the embedding page/query string (much as you can with 
background imagery).

(It might be possible to do what JOSM does by putting the sources on a 
wiki page, rather than relying on a commit to the P2 repository, but I'm 
always a bit wary of people adding Google imagery etc. without us 
noticing. Any thoughts?)

For 2; we could add a new menu like the 'Background' one showing data 
layers in the current area.

cheers
Richard