[georss] Styling GeoRss points

[Sean Gillies]

Charlie Savage wrote:
> 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
> 

Charlie,

Have you ruled out CSS background-image for icon style?

.placemark {
   background-image: url(cliche-pushpin.png);
}

I used this in a customized OpenLayers app.

Sean
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