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Aerial Overview Digital Data Standards
(2001 - ArcView Version)

GENERAL:

Forest Health ‘points’ and ‘polygons’ as recorded on the paper mapsheets during the overview survey flight (scale typically 1:100,00 or 1:250,000 but can be larger - Cariboo Region uses 1:40,000 mapsheets for example) will be digitized on an appropriate electronic map base (typically 1:100,000 scale) - including simultaneous capture of associated attributes. Attributes will include pest code, damage class, etc.

SPECIFICATIONS:

File Format:

All spatial data provided to the Ministry of Forests must be in ESRI ArcView (shape) File format in Albers Equal Area Projection, NAD 83 Datum.

Input Scale:

Standardized blank district boundaries will be used for digital data capture and are provided on the MOF ftp server at:

ftp://ftp.for.gov.bc.ca/hfp/external/!publish/aerial_overview/

Positional Accuracy:

Captured spatial data must have a positional accuracy of 1mm at map scale (for 1:100,000 this is 100 m on the ground) when compared to the original paper map 90 percent of the time.

File Content:

The Positional Files will contain arcs and labels for the polygonal information and points and labels for the point data. The data will be structured, topologically valid, and tied (one-to-one relationship) appropriately to the Arc/Info database. The label numbers will provide the link to the attribute database file (node_num). The database will be output in an MS Access format (posted on the MOF ftp site) and consist of the following attributes:

Database structure:

Attribute	Description	Type	Length	Values
Node_number	Unique centroid Number	Integer	5	Unique number per mapsheet in the range 1-32,000
Region	Region code	Character	3	3 letter Region code (e.g. RVA = Vancouver Region), see Appendix I
District	District code	Character	3	3 letter District Code (e.g. DKA = Kamloops District), see Appendix I
Year	Year of Infestation	Integer	4
Map_number	BCGS Mapsheet	Character	9	e.g. 082fse (1:100,000) 092b105 9 (1:50,000) 104H002 (1:20,000)
FHF	Forest Health Factor (aka: pest code, damage agent and condition code)	Character	3	3 letter code as per FS 747 HSP 99/1 form
Severity	Severity (aka damage class, attack intensity class	Character	1	L(ight), M(oderate), S(evere) NOTE: spot infestations always assigned S(evere)
Polygon_area	Large area of infestation	I*2	8	calculated from positional data, largest area = 99999.99 ha
Spot	Spot (aka point) infestation	Character	1	Y (es) or N(o)
Num_trees	Number of trees in spot infestation	Integer	2	Number between 1 and 50, value only if spot = Y
Spot_area	Area of spot, assigned depending upon num_trees	I*2	4	Value only if spot = Y, 1-30 trees assigned value of 0.25 ha 30-50 trees assigned value of 0.50 ha

METADATA

Minimum Metadata Specifications for Provincial Aerial Survey Data

All IGDS and Arc/Info data will be in the following format:
Projection: Albers Equal Area
Datum: NAD 83
Units: Metres
Spheroid: GRS 1980
1st standard parallel 50 0 0.000
2nd standard parallel 58 30 0.000
Longitude of central meridian: -126 0 0.00
Latitude of true scale: 45 0 0.000
False easting (metres): 1000000.00000
False northing (metres): 0.00000

Last updated on November 2, 2005
The contact for this web page is: tim.ebata@gov.bc.ca


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Aerial Overview Digital Data Standards (2001 - ArcView Version)

Aerial Overview Digital Data Standards
(2001 - ArcView Version)