From 001ae0d3f17744e515b3852f00cbe9ff98f4f5f8 Mon Sep 17 00:00:00 2001
From: lucidiot
+<rss version="2.0" xmlns:georss="http://www.georss.org/georss"> + <channel> + <item> + <!-- ... --> + <georss:point>-33.8735580,151.2344385</georss:point> + <georss:featureName>Boat Syndication Australia</georss:featureName> + <georss:featureTypeTag>shop</georss:featureTypeTag> + <georss:relationshipTag>has-nothing-to-do-with</georss:relationshipTag> + <georss:elev>5.25</georss:elev> + <georss:floor>0</georss:floor> + <georss:radius>4.5</georss:radius> + </item> + </channel> +</rss> ++
Here's a description of all of those intriguing optional elements:
+<georss:featureName>
<georss:featureTypeTag>
The type of that feature: whether it is a mountain, a country, etc. When unset, it defaults to location
. There are no other defined values, as the intent was to let the community form its own taxonomy.
While neither the original website nor the OGC standard specify any restriction, the official XSD typed it as a QName
, meaning an XML qualified name, or anything you can use as the name of an XML element, with or without a namespace prefix. This means you can use something like sandwich:blt
, but not food:sandwich:blt
because only one colon is allowed, and you cannot use spaces. All examples in both the original website and the OGC standard never use spaces, instead preferring kebab-case. So you should probably limit yourself to a QName, or maybe just to kebab-case.
<georss:relationshipTag>
seen-at
, or a feed of drawings where each drawing was inspired-by
. The default is is-located-at
. The relationship is always from the channel or item to the feature, not the other way around. It has the same confusing definition as a QName as featureTypeTag
.<georss:elev>
<georss:floor>
<georss:radius>
Next time, we will finally do more than just point at things, and use the other geometry types that GeoRSS offers.
+ ]]> +<georss:line>
<georss:box>
<georss:polygon>
Here are some examples of each of those tags:
++<!-- Part of Haaldersbroekerdwarsstraat, a long street name in the Netherlands --> +<georss:line>52.4718867,4.8277792 52.4721926,4.8275892 52.4729501,4.8270419</georss:line> + +<!-- Some random grass not so far away from there --> +<georss:box>52.5662344 4.7976189 52.5676983 4.8013674</georss:box> + +<!-- A building called ESPRESSO at the Very Large Telescope, +because astronomers need coffee to go through the night --> +<georss:polygon> + -24.6273416,-70.4045081 + -24.6273922,-70.4044894 + -24.6274264,-70.4046014 + -24.6274789,-70.4045820 + -24.6276119,-70.4045330 + -24.6275341,-70.4042780 + -24.6274634,-70.4043041 + -24.6274763,-70.4043463 + -24.6273109,-70.4044074 + -24.6273416,-70.4045081 +</georss:polygon> ++
You can only specify one of these geometries at once, along with all the optional elements that I described in the previous post. Those new shapes enable some new interesting use cases for feeds:
+<georss:line>
.<georss:line>
to show where the shadow of the eclipse will be moving on the Earth's surface. Maybe with a <georss:radius>
as the radius of the shadow to do some buffering and not only show the center of that shadow.<channel>
including the location of the weather station, or the area where the reports apply.<georss:polygon>
around the circumference of each featured building.<georss:point>
with a <georss:radius>
to show the precision, or as a <georss:polygon>
showing a triangle of the receivers that detected the signal.<georss:point>
when a stop is skipped or moved, a <georss:line>
when a line gets rerouted, etc.You can probably use any of the geoportals out there, the websites that list open geographical data mostly from governments, and get plenty more ideas for GeoRSS feeds.
+And since we are now done with GeoRSS Simple, we'll look at GeoRSS GML next time.
+ ]]>