cfis : Rendering With Style

Comment on Rendering With Style by Chris Tweedie

Wed, 11 Jul 2007 18:19:08 -0600

I dont disagree that to scale in an enterprise sense, tiled schemes is the best by far but i was just trying to highlight that WMS isnt as bad as everyone seems to make out.

If you are able to “constrain” your mapping project to a distinct number of layers, styles, clients, projection and scales then congratulations, i wish all my mapping projects were that easy!

Certainly taking a bit from both baskets would be to use something like Openlayers to utilise both Tiled schemes as well as dynamic WMS as overlays. Of course the problem then is the lack of interoperability between tiling systems. But thats another story :)

One-size doesnt fit all and i dont think Tiled systems are going to replace WMS. They serve different niches and should really coexist together.

Comment on Rendering With Style by Charlie

Wed, 11 Jul 2007 23:23:09 -0600

Hi Chris,

Thanks for the comment. I think a hybrid solution is definitely a good idea. Standards would certainly be nice - but that’s obviously more of a political issue than a technical one. If enough customers want a standard, OGC, or someone else, will be happy to oblige.

I also agree that one size doesn’t fit all, and there is a place for the extreme flexibility of WMS.

I am curious though - you don’t think there is any place for some simplifications in most mapping applications (trying to hit the 80/20 rule here I suppose)?

Comment on Rendering With Style by Chris Tweedie

Thu, 12 Jul 2007 02:20:49 -0600

Oh definately there is room to move. But its probably too hard to generalise down to a specific set of criteria unless we had some examples to work with

All food for thought anyway.

Comment on Rendering With Style by Sean Gillies

Thu, 12 Jul 2007 10:19:22 -0600

I think the usefulness of toggling any and all map feature layers is overblown. Of course a GIS analyst needs this feature in their desktop application, but a lay-user is relying on us to use our expertise, overlay layers properly, and give them a map that’s both informative and usable. A street map, for example (G/Y/M): the roads, waterways, parks, places of interest, all go together and don’t have much meaning without the others.

Comment on Rendering With Style by Charlie

Thu, 12 Jul 2007 14:06:58 -0600

I’m with Sean. With SIAS we had an HTML client which had a super fancy layer control. It was done as a tree - for example it might look like this:

Transportation
   Road Network
     Interstates
     Main Roads
   Railways
Land
  Parcels

Etc. 95% of web users had no idea what it meant - the most they wanted was 2 or 3 checkboxes to turn groups of things on or off (roads for example).

Anyways, layers are amenable to tiles - each layer gets it own set of tiles. A browser can then put them back together by overlaying the transparent tiles (just as WMS works today).

Comment on Rendering With Style by Chris Tweedie

Thu, 12 Jul 2007 22:40:45 -0600

If you can restrict your project down to a set number of distinct layers then i am all for it. But from my experience, where a project contains many layers/groups/themes/whatever, users enjoy the flexibility of seeing “more” or just seeing “what they want”.

G/Y/M in comparison does not have many data layers but the number of users who immediately want to drape their own data over the tiles should show that people do want customisation. Of course, this flexibility should not come at the expense of a nicely compiled base map and this is where G/Y/M shines.

Comment on Rendering With Style by George Marrows

Fri, 13 Jul 2007 03:11:28 -0600

We did some of this stuff in the latest SIAS 4.1 release. As Steve Bell mentioned in some earlier comments, 4.1 was a complete reimplementation - we switched to a J2EE app server, redid the client using dynamic JSF etc.

One thing we introduced was cached/tiled maps with layering, pretty much as you describe above. The native 4.1 mapping service is clever enough to switch between cached map tiles and dynamic maps if the user does want to change style, but we tried to design the UI to ‘keep users in the cache’.

Another much more minor enhancement addresses your comment about the complexity of theme trees for users - there’s a customisation switch to hide all but the top level, so the theme control then becomes a series of on/off switches. We felt we had to maintain the option of the full tree - like Chris, we have customers who want their maps just so, even in a web app.

Nice blog btw - I’ve been mailing some of your GIS articles round the office (though not the Ruby-ish ones - I keep those for myself :-).

Comment on Rendering With Style by Charlie

Fri, 20 Jul 2007 11:05:07 -0600

Hi George,

Thanks for the SIAS update. Sounds like a nice system you’ve implemented. Curious how J2EE and Magik communicate. Did you use the embedded HTTP server in Magik? Or is it via tics or some such mechanism? Or via the magik-java bridge we built?