[OpenLayers-Dev] Status of vector creation and editing tools

[Christopher Schmidt]

On Thu, Sep 27, 2007 at 08:58:27PM -0400, Stephen Woodbridge wrote:
> Hi OL Devs,
> 
> I am trying to figure out what the current state of vector creation and 
> editing tools are. I have been reading through some of my archived mail
> and reviewing the examples:
> 
> http://openlayers.org/dev/examples/modify-feature.html
> This demo does not seem to support deleting a vertex only adding more.

Hover over a vertex on a selected feature. press 'delete' or 'd'. (note
that 'backspace' and 'delete' are different -- macs have a key called
delete which is really backspace, so you want fn-delete.)

> http://openlayers.org/dev/examples/wfs-t.html
> This is broken at the moment.

The server it is talking to is broken. The code itself is not.
(Directing me to a working GeoServer that people don't mind me futzing
with the data in would fix that.)

> The things I do not see at the moment are:
> 1) any way to attach attributes to a feature or to edit/display 
> attributes of a feature. Obviously features would need to belong to 
> classes and each class of feature would need a schema to define the 
> attributes for the class. Then it would be fairly straight forward to 
> create a simple attribute table deplay/editor.

Features do not need to belong to classes. Now, if you were going to
build an editor you might want to build such a thing, but there is no
reason you  can not build a tool which does arbitrary metadata editing:
the FeatureServer Demo at http://featureserver.org/demo.html does
exactly this. (The reason there is no such example in OpenLayers is that
the UI for good feature editing is hard.)

> 2) shared boundary nodes, or a join node

Not possible in the code, as far as I'm aware. No short term plans to
iimplement (patches, etc.)

> 3) snapping to other features or feature nodes. I would be nice to be 
> able to have a gravity so when you get close to an object the mouse 
> snaps to an edge and tracks along the edge if you are close to it, and 
> if you get close to a vertex on an edge or point it will snap to that.

Implemented in a sandbox by Camptocamp. Targeted for 2.6 or later.

> 4) join two features together to make a single object (maybe server side)

Not possible in the code, as far as I'm aware. No short term plans to
implement (patches, etc.)

> 5) split a line at a point, or polygon with a line or with a boolean op 
> (maybe server side)

Not possible in the code, as far as I'm aware. No short term plans to
implement (patches, etc.) Though I did have one other user come to me
and ask for this, and after thinking about it, I think that it would be
an almost-trivial modification to the modify feature control.d

> Has anyone put together a application that allows for the creation, 
> storing and editing of geometry based on these tools? Beyond the 
> examples. 

I've never actually built an OpenLayers application, but both the
FeatureServer demo and the MetaCarta Labs atompub demo
(http://labs.metacarta.com/atompub/app-demo.html) seem to fit this bill
to me.

> What are you using for the backend storage? It seems like the 
> two backends that I have seen mentioned are geoserver and feature 
> server, others? do either of these support postGIS as the data store?

Both do. I've not heard of any others.

> I think all the above is working in 2.4, is this correct?

Nope. Most of it's 2.5.

> What will be added as part of 2.5? 

Nada.

> What otehr functionality is available in the sandboxes in this arena?

Snapping, versioning/history/rollback, attribute display. 

> This is an exciting area of development. It would be cool if a more 
> complete working demo could be built up based on these tools so it could 
> be used as a spring board to build specific applications from.

That sounds great. Would you like sandbox access to develop it? Or do
you just want to submit a patch when it's ready? Typically, we're very
open with sandbox development, but since this probably wouldn't require
any core library changes, there'rs no reason you couldn't develop it on
your own and ust open a ticket when it's ready. 

Regards,
-- 
Christopher Schmidt
MetaCarta