[georss] Styling GeoRss points

[Charlie Savage]

Hi Ron...

> I suggest that you use OGC terminology here which is also aligned with
> general web terminology.
> 
> Styling:  The process of interpreting geographic or other content for
> presentation - graphically or otherwise.  Content then is concerned with
> modeling something - representing properties of the item of interest.  
> 
> Styling is usually specified by rules that express how to interpret the
> content for presentation whether this is graphical (e.g. SVG, KML) or
> textual (e.g. XHTML) or audible (e.g. VoiceXML) etc.

Yes, agreed, those are good definitions.  Taking XHTML as an example, 
CSS provides rules that tell a browser how to present a given page of 
content which is expressed as markup.

I think the point of disagreement here is that in HTML the IMG tag is 
part of the content and its source cannot be specified using CSS.  The 
same holds true for Atom (with its ICON tag), VML (with its IMAGE tag) 
and SVG (with its IMAGE tag).  Exploring SVG a bit more, you can use CSS 
to change colors, line widths, fill, location, size, opacity, etc - but 
not insert IMAGES or change the source of an image (because IMAGE is 
content not styling/presentation).

The way I interpret the above is that images in the context of HTML/SVG 
are not styling.  Whether that is good design decision or not isn't 
really important, its what the specs do. Clearly SLD and KML take a 
different tact - icons are part of styling of some geographic content.

So that is the crux of my argument...images are not styling in the 
context of HTML/SVG/ATOM and thus associating an icon (an image) with a 
GeoRSS point is content, not styling/presentation.  If you think my 
interpretation is incorrect than you'll disagree with the rest of my 
thinking:

1. Images are presentation in the context of HTML/SVG/ATOM

2. An icon is an image.

3. GeoRSS is generally embedded in Atom/RSS feeds

4. Therefore, in keeping with the spirit of what Atom has done, 
associating an icon with a GeoRSS point should be done by specifying an 
image(s) embedded in the Atom/GeoRSS feed

Not to beat a dead horse - but this is not styling.  If you want to make 
the outline of the image red, or 50% opaque, etc, you need to use some 
out-of-band mechanism such as KML, SLD, CSS - whatever is appropriate 
for your environment.

> While I can't say I understand the real scope of GeoRSS - I think that
> styling rule mechanisms already exist in OGC (SLD - Symbology Encoding)
> and I would think that would be a starting point.  You can then target
> various presentation languages (SVG, KML VoiceXML) from there.

Yes, if you want to style your GeoRSS geometries then these are 
certainly good standards to use (and I would add CSS).

Charlie
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