Changes between Version 20 and Version 21 of MapGuideRfc119

Timestamp:

07/19/11 19:44:29 (14 years ago)

Author:

samwang

Comment:

--

MapGuideRfc119

@@ -34 +34 @@
 
 
-2. Also, we may assign an FDO expression to URL element which designates a layer level URL setting for features, but at the the same time, we may as well would like to override it for a specific feature. For example: the URL xml element has been assigned Fdo expression value
+Current layer definition schema(2.3.0) already defines an element "URL" of type string in "!VectorLayerDefinition" complex type to store URL information. However, this is quite simple and may far from enough for applications. We can enhance this in the following two aspects:
+
+1. Description of the URL. The URL is just a universal resource locator in some certain formats, but we may want to display to user more readable text. For example, when user finds a building whose name is 'Empore State Building' in a map, instead of showing user a URL directly so that he can jump to that link for more detailed information of the building, we could provide more descriptive hint such like 'Visit URL http://xxx.xx for more details of Empore State Building' which is much more user firendly. This URL Description element can also be a string FDO expression. 
+
+2. URL override setting. The URL defined in vector layer definition 2.3.0 is a string FDO exprerssion. This can be very flexible but also raises a problem. Consider a scenario that the URL element has been assigned the following FDO expression
 {{{
-Concat('http://www.map.com/fid=', FeatId)
+Concat('http://map.google.com/fid=', FeatId)
 }}}
-where '!FeatId' property is the property to identify a unique feature of the feature class. The the URL of a feature should be like "http://www.map.com/fid=123" with FeatID=123. When a user wants to change the URL of this feature to something else, e.g a hard coded string "http://www.google.com", we have to specify where to store this value.
+where '!FeatId' property is the property to identify a unique feature of the feature class. So the URL of a feature in this layer should be in the form 'http://map.google.com/fid=[FeatId]' where [FeatId] part will be replaced with the actual '!FeatId' property value for each feature. However if user wants to change the URL of a specific feature(and only this one) which turns to be 'http://map.bing.com/fid=[FeatId]' for some reason. It is obvious that we can not change URL element value that will affect all other features. So what we can do is to specify a property of the feature class that the layer is based on where we can store this overriden value.
   
 == Proposed Solution ==