DATAQUAL.TXT - 8th of 19 digital documentation files distributed
               with the "Forest Fire Chronology of Saskatchewan"
               (FFCS) dataset.


<Document overview>

     Describes elements affecting the quality of the FFCS
     dataset, including thoroughness of the database, data
     verification, topological integrity, and potential mistakes
     or errors in the database.


<Completeness of database>

     Many fires are not in the database due to missing records.
     Some (but not all) of these have been listed by Terry Rock
     in the report associated with this dataset (see
     AUTHORS.TXT).  The FFCS database is only as complete as the
     fire records available to be entered.  By no means should
     the FFCS be viewed as a totally exhaustive dataset.  If you
     are aware of any fires that are missing and have a source
     map for said fires, then please contact the data manager
     listed in METADATA.TXT.


<Data verification>

     The fire boundaries have NOT been ground truthed, primarily
     because it would be far too expensive.  Alternatively, fire
     boundaries could be compared against other map sources that
     would reflect the occurrence of wildfire.  Such sources
     include forest inventory maps, field records, other aerial
     survey information.  Satellite imagery could also be a
     useful tool for verifying fire boundaries.

     Regardless of available burn boundary verification sources,
     it is clear that perimeter verification would result in
     accentuating the already inconsistent quality levels within
     the database.  (Data inconsistency sources are listed in the
     next section).

     The positioning of burn boundaries on the source maps is
     implicitly assumed to be correct.  Yet their positioning may
     be significantly inaccurate.  Similarly, fire boundaries
     defined using Global Positioning System (GPS) dataloggers
     may have been generated by tracking the approximate boundary
     of the fire; corners may have literally been cut while
     tracking.

     Given the medium-to-small scale of the source maps and the
     errors inherent in the original mapped boundaries, check
     plots were not used to verify the digital boundaries.  A
     standard level of digitizing error is simply assumed.


<Consistency of the database>

     The accuracy of the source maps is variable.  In addition to
     having a large number of staff delineating fire boundaries
     and that a variety of mapping methods have been used, data
     consistency variations are a function of spatial and
     temporal factors as well as fire mapping limitations:

      (1) Some smaller burns in or north of the Canadian shield
          may go undetected, and as such, might not be mapped.
          Burns in the commercial forest and around high value
          areas are usually mapped more accurately than those
          further north.
      (2) Conditions at present do not reflect those 50 years
          ago; water levels in lakes and marshes have fluctuated
          in the 50 year span, timber harvesting has not been
          accounted for, etc.  Burns may have been delineated
          using base-maps that only reflect the conditions at the
          time when the base-maps were generated.
      (3) Aerial reconnaissance of burn perimeters is biased
          towards fires that consumed understorey or canopy
          fuels.  Because ground burn perimeters may be
          obstructed by foliage, ground level fires are not
          mapped as accurately as the other fires.

     The use of Global Positioning Systems, lightning strike
     detectors and better communication equipment means that more
     fires today are detected, monitored, and mapped than in
     1940s, 1950s and 1960s.

     As the FFCS dataset spans a fifty year period, the
     administrative codes used in FFMBs fire numbering scheme
     will NOT necessarily represent the same administrative
     boundaries.  (The administrative codes have only been added
     to fires from 1990 onward).  The administrative boundaries
     have often been shifted, aggregated, or split.  They are
     unlikely to ever be permanent.  The administrative
     boundaries hence are not a basis for summarizing data over
     extended periods of time.


<Topological data integrity>

     All fire boundaries coverages should not have any dangles,
     slivers, labelerrors or unnecessary nodes (see
     TOPOLOGY.TXT).


<Mistakes or errors in the database>

     Should you find any errors in the documentation, the spatial
     database or the attribute databases, then please notify the
     data manager (as listed in METADATA.TXT).  Every attempt has
     been made to avoid topological and typographical errors.
     Nevertheless, the FFCS dataset may be missing some fires or
     it may contain inaccurate information.  By contacting the
     data author about such errors, corrections can be made at
     the source and subsequent distributions of the dataset will
     contain the corrected information.


This document prepared by:

Ott Naelapea
Wildlife Branch
Saskatchewan Environment & Resource Management
Box 3003, 800 Central Avenue
Prince Albert, SK.  S6V 6G1
CANADA
(306)953-2671 - Tel.
(306)953-2750 - Fax.

November 28, 1996
