Routes to be followed in the field are normally determined by the mapper from air photo interpretation (Section 6.0). Polygons that require checking, exposures, and other places to visit are grouped into a series of day-long traverses. Either formally defined transects or sequences of random spot checks can be used. Travel in the map area may be on foot, by vehicle, by helicopter, or any combination. Mode of travel is usually related at least in part to the scale of the mapping (Table 7).
Field observations are not restricted to those at formally designated sites: many observations are made in places other than those where data forms are completed. Useful data can be gathered when traveling from one observation site to the next. In particular, the position of terrain unit boundaries should be checked against visible features at every boundary that is crossed in the field. Casual observations of ground surface conditions, roadcuts and stream banks should be made continuously. Features such as erratic boulders, angular versus rounded clasts, high water table, soil texture, materials exposed in the roots of fallen trees, and material excavated from animal burrows all provide usefuI information. Ice flow direction should be recorded if glacial striations or other flow direction indicators are found. Checking of remote sites with binoculars is a useful, time-saving technique: for example, distant hillsides can be searched for rock outcrops, and inaccessible sections can be more closely examined. (Sites that are not actually visited should not be designated as formal observation sites.) Information gathered during travel between formal sites can be recorded directly on air photos or in field notebooks, and eventually entered into a polygon data file (Appendix E). Routine observations that confirm polygon descriptions already on the air photos need not be noted.
During field work with a helicopter, many valuable observations can be made from the air. If the mapper compares pretyped data on air photos with land surface characteristics visible from slow, low-level flight, many terrain characteristics can be confirmed or corrected. Exposures of surficial materials that are not near landing sites (steep river banks and gullies, for example) can be briefly examined from a hovering aircraft and photographed. (An inexperienced mapper should be aware that the visual appearance of materials in sections partly obscured by surface wash can be misleading.)
Use of a data form with a fixed format for recording observation site information encourages collection of a standard data set, maintains consistency between different mappers, and facilitates data entry to computer storage and subsequent processing.
Minimum Requirement:
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The objectives and terms of reference of many projects require the use of specific forms and coding systems. For other projects, mappers should design their own data form according to project objectives. Examples of sample data forms are provided in Figure 7. Existing coding systems can be used for recording field data appropriate to project objectives. Examples include the lithofacies code of Eyles et al. (1983) and the Unified Soil Classification System as described in all North American soil mechanics text books (Appendix D). Mitchell (1991) provides several other examples for generalized and specialized terrain mapping as does an excellent publication by the US Bureau of Reclamation (1989).
Use of forms for data recording does not preclude the collection of additional relevant data in field notebooks, e.g., sketches of exposures. Table 10 shows data that are routinely collected by most terrain mappers, as well as minimum requirements. It is normal to collect varying amounts of information from different sites, as determined by the nature of each site. Active geomorphic processes and hydrologic features are not apparent at many sites, and stratigraphic information is not normally obtained from a "soil pit".
The mandate of the Resources Inventory Committee (RIC) is to develop inventory standards and guidelines for British Columbia. Besides the information presented elsewhere in this document, the Terrain Mapping Guidelines and Standards is also concerned with the digital capture of information (Appendix E) and the graphic representation and standardization of symbols (Appendix I). Appendix E provides an outline of a data model suitable for the digital storage, access, presentation and interpretation of terrain and surficial geology data.
The model presented here is similar to the model produced by the Archeology Task Group for the Data Model Rational Project of RIC (DMR Group Inc., 1993) and is presented in a format suitable to RIC (e.g. RIC, 1992). Development of the model presented here relies on products by the Archeology Branch, B.C. Ministry of Small Business, Tourism and Culture (~: DMR Group Inc., 1993) and the Surveys and Resources Mapping Branch, B.C. Ministry of Environment, Lands and Parks (MELP).
Data models/databases from other agencies were solicited and reviewed. These included:
The data model has been developed in a hierarchical form, and follows the format established by RIC (1992). An outline of the hierarchy is shown in Figure 8. An expanded summary of the hierarchy, along with the suggested computer acronyms, is presented in Table 11. The hierarchy follows a logical progression, and includes all possible data that might be included in the collection, interpretation and presentation of terrain and surficial geology data. The full data model, showing all fields/attributes and the data types is presented in Appendix E. This full data model also follows the format established by RIC (1992). To clarify and further expand the data model, comments, examples and references to lists of values have been included in the right hand column.
When collecting and recording information at a particular observation/sample site, it is common that more than one set of similar data are collected. For example when two distinct stratigraphic terrain units occur in the exposure, or when two or more photos are taken of the site. These types of situations are accounted for in the data model by using multiple entries or records, as indicated on the f 11 data model in Appendix E.
It is not intended that all information in the f 11 data model would or should be collected. A minimum amount of data, however, are required. The suggested minimum data is highlighted with an asterisk (*) in the left hand column of the full data model (Appendix E). The minimum requirements for data collection is summarized below in Table 12. It should be reiterated that the terrain data model is still in DRAFT form, but the minimum requirements for data collection are part of the standards.