Hi,
I was meaning that a diagram could be a part of a proposal. See a sketch at http://latuviitta.org/documents/Geoserver_layer_group_sketch.pdf
I was wrong with the missing title in some Mapserver services. Mapserver writes a comment about missing metadata element into GetCapabilities but it does also add a default Title for group. I do not bother to make a new sketch because it is just a trial to clarify my thoughts anyway.
I think it is not good that QGIS is expanding the root layer without a name. It means that all the layers on the service get selected and usually it would make no sense at all. I have not tried what if there are subgroups which are configured in a similar way further in the tree without names. If those groups are expanded into a list of all the layers belonging to the group it could lead to a similar non-usable map. For example we have an orthophoto group which contains layers for each year and it does not make sense to select all the layers together.
I understand these three types of groups:
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Category group for making it possible to make better readable layer tree with something like census data maps/historical maps/orthophotos. Layers in the group are not meant to be looked all together automatically. User selects each layer individually.
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Groups which are sometimes used all together but not always. User can select either the whole group by group name or individual layers.
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Groups containing layers which are always used together. Only Geoserver knows that they are groups because layer names are hidden from the user.
I suppose that EO will bring a fourth group type but I have not studied it yet.
-Jukka-
···
Andrea Aime wrote
On Mon, Dec 17, 2012 at 12:59 PM, Rahkonen Jukka <Jukka.Rahkonen@anonymised.com> wrote:
Hi,
+1 if I have understood the proposal right as I suppose.
A diagram showing a tree with all these options, a screen capture about the tree shown by an imaginary well designed client, and a few more showing what happens if user selects the group level as WMS layer would be helpful. Also and especially later to be included in the user documentation.
It feels that for showing all this information for the user the application should show both titles and names for the layers and groups. At least screens of mobile clients may get crowded but that is another problem.
Unfortunately I don’t have anything like that, we do proposals before writing code so I cannot have
those screenshots.
Title and name have different uses: the “name” is meant for computers to be used in calls
to GetMap/GetFeatureInfo, while “title” is meant to be shown to the end users by clients.
Title is always present, Name not necessarily.
I had a very quick look and I think that QGIS is doing wrong with groups without names but with title. If group is selected it selects all the layers even it should select none. Good thing is that QGIS shows names, titles and abstracts for all the layers. OpenJUMP seems to do the right thing with groups having only a title, it does not select layers then.
Both behaviors seem legit to me.
If qgis allows visual selection of the root layer, and the root layer has no name, it’s reasonable that it expands the list of layers underneath it.
It’s a GUI interaction thing, the capabilities document is just a “catalog” of information, the client uses it as it sees fit.
OpenJUMP behavior seems also reasonable, but a bit restrictive, but if it does not allow the user to select the root of the group I believe it’s fine.
Cheers
Andrea
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