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Subject: RE: [emergency] Info Model 2005-06-20 (GIS comments)
Folks, This is meant to be a summary of what I was trying to say during today's GIS subcommittee meeting. The basic gist is that, because of the EDXL Distribution Element's information structure, we can have our cake and eat it too. Basic suggestions: 1. Leave CAP alone for now with repect to WGS 84 and its Area structure. It is gaining traction and changing it now would cause enough loss of momentum that the whole effort at EM standards could be hurt. 2. That said, we must address the issues of GML and difference in representation, as it applies to the distribution element, and distribution content (to include CAP). This can be done by recognizing and using the information structure of the distribution element. 3. The "targetArea" of the element is designed to carry only the "boundary of interest" for the enclosed messages. As such it must be simple, flat, and quick to process by intermediate processes (e.g., message brokers) that may not even try to process the details of the message content. While we agree that GML is an excellent standard and highly appropriate for geographic information, we have not yet seen the particular set of simple GML geometries that meet the needs of targetArea. But we will. Carl has promised to provide. Once evaluated, it is probable that a simple GML boundary representaion for polygon and circle will be approved for the EDXL distribution Area block. (We may also consider this structure for CAP, but not until version 2.0). 4. There will be a need for the transmission of more complex (or just different) geographic elements in context with a CAP message or with other messages using EDXL Distribution. In such cases that content can be added as one or more additional Content Messages under a single the EDXL Distribution Element. XML content will follow the rules of the XML Object which allow embedded constructs using other referenceable standards or named structures to be included with the larger message. In ths way SensorXML, IEE 1512, CAP, GJXDM and other content can be combined for transmission without losing native format. Non-XML content content will follow the rules of the Content Object structure allowing for embedding objects using MIME type or referencing the location of external objects for separate retreival. KEY CONCEPT: Content Messages will follow their own referenceable standard (open or proprietary). Distribution engines will not be required to understand the rules of Content Objects, but recipients will be expected to 1) determine if they can process content and 2) process what they can. This encapsualtion of content makes it easier to manage a distribution engine without limiting the content it can process. (Content-based distribution engines will have two ways to deal with their issues: process the content-oriented keywords in the distribution element and/or 2) read and process the content of thoes Content Messages that they understand while ignoring those that they do not understand.) Still under consideration might be a standard response from a recipient unable to read content back to its originator. (I do not know if this would even be a requirement, but it might for certain specialized use cases.) Gary A. Ham Senior Research Scientist Battelle Memorial Institute 540-288-5611 (office) 703-869-6241 (cell) "You would be surprised what you can accomplish when you do not care who gets the credit." - Harry S. Truman -----Original Message----- From: Renato Iannella [mailto:email@example.com] Sent: Monday, June 20, 2005 2:06 AM To: Emergency_Mgt_TC TC Subject: [emergency] Info Model 2005-06-20 Dear all, attached is the draft EDXL Information Model and Semantics document. It provides an Information Model (to supplement the original data model) and uses ISO11179 model to define the semantics for each element. I have also tried to name the elements based on their role (eg External Object) rather than their data type (eg URI). I have tried to include the outcomes from the recent discussions as well (eg spatial refs, list terms). I do expect a lot more discussion on the content, and please don't assume that the current model, elements, etc are in anyway final (or even close! ;-) Cheers... Renato Iannella Project Leader, NICTA, Brisbane, QLD, AUSTRALIA P: +61 7 3000 0484 F: +61 7 3000 0480 M: +61 4 1313 2206 E: firstname.lastname@example.org W: http://nicta.com.au ------------------------------------------------------------------------ -- This email and any attachments may be confidential. They may contain legally privileged information or copyright material. You should not read, copy, use or disclose them without authorisation. If you are not an intended recipient, please contact us at once by return email and then delete both messages. We do not accept liability in connection with computer virus, data corruption, delay, interruption, unauthorised access or unauthorised amendment. This notice should not be removed.