2010/5/17 Jody Garnett
<jody.garnett@xxxxxxxxx>
HI Frank:
I am just hitting a customer delivery today; and releasing uDig 1.2-RC at the same time.
I am sorry if I muddled our earlier communication; you will find that uDig already combines two layers together into one request whenever they appear next to each other in the draw order.
Jody
Don't mind!
On 17/05/2010, at 3:20 PM, Frank Gasdorf wrote:
> Hi Jody,
>
> After a few day of thinking I'd like to answer you and probably I have to clarify my thought.
> - 1st: udig supports WMS servers that provided a hierarchy of layers... you can see these in the catalog view when selecting layers to
> Thanks for that! I tested it with an ags service (capabilities looks like the pseudo code sended before). Within the catalog view and the wizard the hierarchy is mapped but I the user chooses sublayer(s) the app added a Map layer for each sublayer in the Layer-View.
> What I would like to expect right here are two use cases:
> 1. Add a single Hierarchy layer (user choice) and enable the selected layers, all others are deselected (disabled)
> 2. Add for each sub layer a single map-layer and let the user choose the order and enablement
>
> In the projects with my costumers I found out, the first bullet would be great form point of the user. In these organisations the admins of the services are not the users, therefore the users don't want to define the content of the service, its layout and filters of data. The users only want to consume a well defined map service, maybe enable/disable a single sublayer or group.
Usually the groups in WMS don't work like that; the parent represents rendering all the children in one go. And often the parent represents one kind of data; and the children represent the same kind of data (at different scales).
I agree, but it should be possible to enable or disable sub layers or whole groups. That may result into a special server side caching administration ...
> The later in my opinion is quite better if users want to consume single layers out of complex services and combine these with (many) different layers of other services.
I worked a lot on the table of contents code on the weekend; it is terrible but now runs :-) You can organise the presentation of layers to your user however makes sense for them; uDig internally will group them into a zorder and worry about visibility etc... but there is really no need to show users that.
Sounds good. I'd like to have a look at :)
> I guess you are the maintainer of the WMS stuff, aren't you? How is the request to the service generated for the renderer for both use cases (see above)? Would/ is it (be) a single request for as many layers as the users added from one service or is it a single request per layer? Sorry, I didn't grabbed the source so far...
Both are possible; however there is a difference between:
A
- b
- c
If the user requests "b,c" uDig should be able to request "A" and be happy as "A" is probably cached by the server for speed.
If the user requests "c,b" then uDig needs to issue a single request for "c,b" - which may be slower.
I would say, sub layers should be not changeable in order, because the service is (hopefully ) well designed in groups. We created groups per scale range in a project and defined point- on top of line- on top of polyline -featurelayers. Later maybe transparent if there are some raster layers as well.
> - 2nd: perhaps we can show the "children" of a parent WMS layer in this new "legend" view?
>
> That would be nice. Is it already implemented or a feature request? Are there any implementations in other projects which uses uDig? Do you know some of these?
It was an idea I had while talking to you; since the Table of Content view (I want to call it legend view). The contents of a folder do not have to be layers; indeed right now you can "open" a layer and show the different feature type styles defined by its SLD.
TOC is also ags wording - do you really prefer this ;)
I will do my best to upload this puppy as a community plugin this week.
Cheers,
Jody
