4.0 Overall Mapping and Database Structure
This mapping system is composed of seven individual databases / digital coverages that are inter-linked and designed to separate administrative from mapping data, biological from physical data, polygon from point data, and small scale data from large scale data (Figure 3). The project database contains high level administrative information on the project that can be easily accessed for those interested in the project details. The estuary overview database stores information related to the overall character of the estuary and adjacent terrestrial and marine areas, including - for example - basin size and wave exposure. The estuary overview database captures small scale (large area) information that are common to the points and polygons of the other more large scale databases. The physical unit database stores polygon information acquired from airphoto interpretation and field survey, using codes and definitions primarily from the BC Physical Shore Zone Mapping System, and to a lesser extent from the Terrain Classification System. The information in the physical unit database is also attached to an ARC/INFO coverage. The biological unit database stores polygon information pertaining to the WREC class/site series and BC Biological Shore Zone Mapping System bio-bands. The information in the biological unit database is acquired by a combination of airphoto interpretation in conjunction with field survey, and is incorporated into an ARC/INFO coverage. It is important to note that the physical unit and biological unit databases (including mapped databases) are kept separate in this standard. The elevation zone database maps similar elevation zones from the marine limit to the 20 metre isobath relative to the chart datum (zero tide) in an ARC/INFO coverage. The biological site database is a point database that captures information from detailed field plots used to verify the site series/bio-bands. The physical site database is a point database used to capture forms and materials from detailed survey plots.
Figure 3 - A Schematic diagram of the seven databases used in the British Columbia Estuary Mapping System.
The project database contains high level administrative information on the project. The estuary overview database stores general information on the estuary and its surroundings. Field names, types, widths and descriptions are outlined in Table 1. Note the EstuaryID is the field used to link all the estuary databases, and is common to all databases.
Table 1 - Description of the Project Database.
Field Name |
Type |
Width of Field |
Description |
Estuary |
Alpha |
50 |
Name of Estuary |
EstuaryID |
Alphanumeric |
14 |
Unique identifier for Estuary (eg. SEYMWSD0001890x). Determined from Watershed Atlas |
Date |
Date |
10 |
Day/month/year (eg. 02/12/1999) |
Agency |
Alpha |
50 |
Name of Government Agency responsible for project |
Scale |
Numeric |
7 |
Scale of mapping (eg. 10,000) |
Mapsheet |
Alphanumeric |
6 |
NTS / TRIM Sheet number (eg. 93H3) |
Chart |
Numeric |
8 |
CHS chart number |
Pdata_src |
Alphanumeric |
50 |
Data source (eg. NTS sheet, CHS chart, aerial photo) |
Notes |
Alpha |
255 |
Notes on data source |
The estuary overview database is designed for comparisons between estuaries, and contains items that are related to the estuary as a single unit (e.g. area, drainage basin size, etc.) Field names, types, widths and descriptions are supplied in Table 2.
Table 2 - Description of the Estuary Overview database.
Field Name |
Type |
Width of Field |
Description |
EstuaryID |
Alphanumeric |
14 |
Unique identifier for Estuary (eg. SEYMWSD0001890x) |
Estarea |
Numeric |
10 |
Total area of the Estuary in square meters |
Interarea |
Numeric |
10 |
Total area of the Intertidal in square meters |
Subarea |
Numeric |
10 |
Total area of the Subtidal in square meters |
DomIN |
Alpha |
2 |
Dominant material in the Intertidal ( g - gravel s - sands) |
Subslope |
Numeric |
3 |
Slope of the subtidal zone (degrees) |
Intslope |
Numeric |
3 |
Slope of the intertidal zone (degrees) |
Watershed |
Alpha |
50 |
Watershed name (from FISS) |
Shedarea |
Numeric |
10 |
Total area of the Watershed in square meters |
Dispeak |
Numeric |
10 |
Peak monthly discharge in cubic meters per second |
Dispmon |
Alpha |
3 |
Month of peak discharge |
Dispan |
Numeric |
10 |
Annual peak discharge in cubic meters per second |
Dismin |
Numeric |
10 |
Monthly minimum discharge in cubic meters per second |
Dismmon |
Alpha |
10 |
Month of minimum discharge |
Dismann |
Numeric |
10 |
Annual minimum discharge in cubic meters per second |
Dis_src |
Alpha |
255 |
Source of discharge |
Exposure |
Alpha |
2 |
Wave exposure code (eg. P - Protected SE - Semi-exposed) (refer to Appendix A) |
Orientation |
Numeric |
3 |
Orientation of estuary in degrees (aspect) |
Marsection |
Alpha |
25 |
Ecosection from the BC Marine Ecological Classification |
Marunit |
Alpha |
7 |
Ecounit from the BC Marine Ecological Classification |
Ecosection |
Alpha |
25 |
Terrestrial ecosection |
Beclabel |
Alphanumeric |
9 |
Biogeoclimatic zone identifier |
Phy_ident |
Alpha |
13 |
Physical shoreline identifier (if available) from BC Physical Shore-zone Mapping System (eg. 03/04/0056/00) |
Mapper |
Alpha |
25 |
Name of mapper (last name, first name) |
Most of the items in the estuary overview database can be calculated using a GIS, or from basemaps (e.g. TRIM or hydrographic charts). Discharge rates can be obtained from the BC Ministry of Fisheries. Wave exposure can be obtained from the BC Physical Shore Zone Mapping System, or through the wave exposure calculation provided in Appendix A (Howes et al. 1994).
