CAP and GIS, con call on June 17

[Eliot Christian <echristi@usgs.gov>]

I would like to invite participation in a conference call of
the GIS SC on Tuesday, June 17 at noon, Eastern Time. The call-in
number is 800-453-7412 and the access code is 604776

Per a recent note on the "Messages and Notifications SC" list,
the Common Alerting Protocol (CAP) Data Dictionary is being
finalized. In the attached PDF, you will see several items that
address guidance provided by our GIS Subcommittee (extracted here
below).

If you have any comments or suggestions on review of these element
dictionary entries, please post to this SC list immediately.

Eliot

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Part 3 -"area" Element and Sub-elements

area

   The container for all component parts of the area sub-element
   of the info sub-element of the alert message (optional)

   (1) May only occur within an <info>.
   (2) Multiple occurrences are permitted within a single <info>,
   in which case the target area for that "info" block is the union
   of all the included "area" blocks.
   (3) May contain one or multiple instances of <polygon>, <radius>
   or <geocode>. If multiple <polygon>, <radius> or <geocode>
   elements are included, the area defined is the union of those
   represented by all of the included elements.

areaDesc

   The text describing the affected area of the alert message
   (mandatory)

polygon

   The group listing of the polygons delineating the affected area
   of the alert message (optional)

   (1) Code Values: The geographic polygon is represented by a
   whitespace-delimited list of WGS-84 coordinate values
   [see WGS-84 Note].
   (2) Multiple instances may occur within a single "area" block.

radius

   The paired values of a point and radius delineating the affected
   area of the alert message (optional)

   (1) Code Values: The circular area is represented by a central
   point given as a WGS-84 coordinate value [see WGS-84 Note],
   followed by a space character and a radius value in kilometers.
   (2) Multiple instances may occur within a single "area" block.

geocode

   The geographic code delineating the affected area of the alert
   message (optional)

   (1) Code Values: Any geographically-based code to describe
   message target area, in the form "code_ type= code" where
   "code_ type" is a user-assigned abbreviation for the target
   system (e.g,, " fips= 06003 "). May not include spaces or
   XML-restricted characters (<, >, &, ',").
   (2) Multiple instances may occur within a single "area" block.
   (3) Use of this element presumes prior knowledge of the coding
   system on the part of recipients; therefore, its use
   unaccompanied by equivalent and more generally understood
   <polygon> or <radius> representations should be avoided when
   possible.

altitude

   The specific or minimum altitude of the affected area of the
   alert message (optional)

   (1) If used with the <ceiling> element this value is the lower
   limit of a range. Otherwise, this value specifies a specific
   altitude.
   (2) The altitude measure is in feet above mean sea level
   (per WGS-84 datum).

ceiling

   The maximum altitude of the affected area of the alert message
   (conditional)

   (1) May only be used in combination with the <altitude> element
   (2) The altitude measure is in feet above mean sea level
   (per WGS-84 datum).

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WGS-84 Note: Geographic locations in CAP are defined using WGS 84
   (World Geodetic System 1984), equivalent to EPSG (European
   Petroleum Survey Group) code 4326 (2 dimensions). CAP does not
   assign responsibilities for coordinate transformations from and
   to other Spatial Reference Systems. A WGS-84 coordinate value is
   here represented as a comma-delimited latitude/ longitude pair,
   measured in decimal degrees (un-projected). Latitudes range from
   -90 to 90 and longitudes range from -180 to 180. Coordinates in
   the Southern and Western hemispheres are signed negative with a
   leading dash.

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CAP_0.8a_DOM_and_Dict.pdf