Location References for CAP-CP Beta 0.3B

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Purpose of this Document

This document identifies the specific alert location references to be used, in order to satisfy the requirements of the Common Alerting Protocol - Canadian Profile (CAP-CP).

This document is versioned independently of CAP-CP rules included in the CAP-CP Introduction and Rule Set document, since it applies directly to the business of public alerting, rather than the specifics of XML formatting and structure. The location list is expected to be updated more frequently than the rule set which addresses the CAP-CP position on CAP formatting and structure.

Authors

The principal authors of this document version are listed below in alphabetic order:

Copyright

Copyright  2010. This document may be reproduced, without charge or request for permission, provided it is reproduced in its entirety and without modification.

Notices

This document and the information contained herein is provided on an "AS IS" basis and the Authors, and their officers, employees or agents DISCLAIM ALL WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY OR REPRESENTATION THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE RIGHTS OF OTHERS, OR ANY IMPLIED WARRANTIES OR REPRESENTATIONS OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Revision Summary

This version includes the following updates:

  1. References the 2010 update to the 2006 Standard Geographical Classification (SGC) from Statistics Canada

Other CAP-CP Documents

The entire CAP-CP is defined in this document, and the following two additional documents:

  1. CAP-CP Introduction and Rule Set. This document details the specific requirements, constraints, and recommendations associated with the Canadian Profile of the CAP. It is versioned independently of this document.
  2. CAP-CP Event References. This document details a comprehensive list of recognized events associated with Public Alerting in Canada. It is versioned independently of this document.

To ensure access to CAP-CP by public alerting stakeholders as soon as possible, all three documents are available at the following web sites:

CAP-CP may also be available on other websites. Where there is a difference in versions, the version at www.CAPAN.ca/CAP-CP shall take precedence. New versions shall be created only with the express consent of the authors listed in this document.

Associated Documents and Resources

  1. The 2009 update to the 2006 Statistics Canada - Standard Geographical Classification (SGC) is available from the CAPAN website, at www.CAPAN.ca/CAP-CP. It is not an official Statistics Canada document, and cannot therefore be found on the Statistics Canada website. The information it contains, however, can be derived from the 2009 Statistics Canada SGC boundary files.
  2. www.CAPAN.ca/CAP-CP. The CAP-CP website identifies other CAP-CP related resources.

Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in IETF RFC 2119, available at http://www.ietf.org/rfc/rfc2119.txt

Additional terminology is specified in the CAP-CP Introduction and Rule Set document.

Development of CAP-CP as a National Standard of Canada

The authors of CAP-CP are giving consideration to submitting the profile to a Canadian standards development organization (SDO) for development as a National Standard of Canada. This, they anticipate, will ensure a recognized process in the decision-making regarding elements of the standard on an initial and ongoing basis, and will also ensure clarity and access to the standard for all public alerting stakeholders. With the formal initiation of the standard development process, the SDO would become the custodian and manager of CAP-CP.

CAP-CP Location Requirements

CAP-CP rules currently require originators of alerts to identify appropriate location geocode(s) for which, or within which, the subject of the alert message pertains. CAP-CP geocode requirements are only minimum requirements and are subject to gross over estimations of the area to be alerted. This requirement will be deprecated, and developers are encouraged to plan for such changes. Therefore, users of CAP-CP messages with GIS capabilities are encouraged to provide and distribute to the more specific information that can be found in the polygon and or circle elements, when such values are present.

For terrestrial areas, the locations are identified using geocode(s) that have their basis in the Statistics Canada Standard Geographical Classification (SGC). Marine areas are not yet finalized for CAP-CP, although Environment Canada marine areas are under consideration.

The textual description (areaDesc) need not include the actual names associated with the geocodes, however, their inclusion is encouraged where the area otherwise described would not be familiar to visitors to the region.

The rest of this document describes the use of the geocodes.

Standard Geographical Classification (SGC)

SGC are defined and maintained in Canada by Statistics Canada. Every five years Statistics Canada issues a full SGC update with documentation in step with the national census. Between these major issues, changes do occur, and Statistics Canada shares these updates in the form of lists and updated geographic boundary files. These updates reflect the changes with provincial recognition of newly incorporated areas, newly amalgamated areas, etc.   The goal of the CAP-CP will be to attempt to keep current with these intermediate updates.

Note however, that CAP-CP Location references are only based on the SGC as of early 2010. Therefore, whenever an SGC update occurs, additional work is needed within the CAP-CP world to consider possible new issues as well as fill in any gaps in the CAP-CP Location References documentation. This means that CAP-CP Location reference updates will be scheduled a period of time after the corresponding SGC updates occur.

The Statistics Canada information page for SGC, at the time of writing, is located at the following URL: http://www.statcan.gc.ca/subjects-sujets/standard-norme/sgc-cgt/2006/2006-intro-fin-eng.htm#a3 SGC values are available for free, and related geomatics data for a fee, on Statistics Canada's website.

The SGC codes to be used with CAP-CP are as follows:

  1. National
  2. Province / Territory
  3. Census Division (CD), which pertains to provincial or territorial legislated locations typically referenced as a county or region. The combination of CDs for a province/territory equals the combined area of the province/territory.
  4. Census Sub-Division (CSD), which pertains to municipalities and Indian reserves. CSDs are combined geographically to form a CD.

Where a higher level SGC code is applicable, CAP-CP recommends the use of the higher level code. For example, when the area pertains to an entire CD, the CD code should be used rather than listing each of the CSD codes that make up the CD.

As noted above, new issues may arise with SGC updates, however there are a couple of known issues already that need some comment. For example, certain CSD's are large areas that have holes (ie a Swiss cheese affect). In most cases, these areas are CSD's representing unincorporated, less populated areas of a CD that surrounds all the populated communities (CSD's), with the holes being the communities themselves. While further research is required, and to be undertaken before any changes to the lists are made, the authors see no need to use such area references, and are considering the removal of such codes from future versions of the CAP-CP location references.

Given that CAP-CP may be used by Canadian originators for alerts which pertain to areas outside of the country, CAP-CP also provides an add-on value for alerts which are issued for areas outside of the country. The value is “none”, and it is not case sensitive. Until such time as Canadian marine location references are included in CAP-CP, the “none” value is also to be used for marine areas. Note, that this last requirement does not preclude the inclusion of a marine area reference, as CAP does support multiple location references.

SGC Reference Version

This CAP-CP Location References document includes the updates to the SGC 2006 found in the May 2010 SGC boundary files. The boundary files can be found at http://geodepot.statcan.ca/Diss2006/DataProducts/CSD_e.jsp. A table of SGC values which includes name, number and type is available at www.CAPAN.ca/CAP-CP, and other websites previously referenced, for the convenience of CAP-CP implementers.

Marine Values

Values for marine areas are being evaluated and are subject to several additional considerations. The first of these involves the fact that the terrestrial SGC codes from Statistics Canada extend out into the water whenever a SGC zone borders a shoreline. This brings up the issue that marine geocoded zones may have overlapping areas with terrestrial zones near shorelines if the marine areas snap to the shoreline or extend inland. For Inland water bodies there will be the additional consideration of the size of the water body in question.

More importantly though is the need to make sure that whatever marine geocode system is eventually employed, it is true to the intent of alert messaging over marine areas. In the absence of marine geocodes, the ability to create alert messages over water is still possible with the more accurate and more preferred use of polygons. In such cases where the polygon is to represents a marine area, the value to use for the geocode element would be “none” (see appendix).

CAPAN has published a set of proposed location references for marine areas based on Environment Canada's marine area references. They may be used in combination with the “none” value.

English and French Location Names

At the time of writing, Statistics Canada publishes SGC codes with one place name value for each entry, as provided to them by the province or territory to which they pertain. Some SGC place names are in English, some are in French, and a few include both English and French values.

Presentation in the CAP-CP <area> Block

SGC codes are to be presented using the CAP <geocode> element.

The <valueName> SHALL be formatted as specified in the CAP-CP rules set, and set forth in the next section.

Location Reference <valueName>

CAP-CP has adopted a URN-like scheme for creating valueNames. Location reference valueNames use the following format:

profile:CAP-CP:Location:<version number>

As mentioned previously, the versioning of the CAP-CP Location References document is independent of the other CAP-CP documents. Where a change is non-substantive, such as the change herein which relates to an update to a third party list, the version number will not change.

The following <valueName> is defined for this version of the Location References document,

profile:CAP-CP:Location:0.3

Appendix:

CAP-CP Location Values

The following values are CAP-CP custom additions, which may be used in addition to the SGC values. This table is expected to grow over time as other location related challenges are identified and addressed.

CAP-CP Location Values

CAP-CP geocode Value

Description

none

Area of alert cannot be associated with a current CAP-CP location code, as it is outside Canada or in a marine area of Canada. There may be other examples. The value “none” is not case sensitive.

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