8.0 Methodology IV: Compiling the Terrain Map
Following field work, terrain mapping is corrected on the air photos, and a final consistency check is made of all mapped photos. All adjacent photo edges should be checked for continuity of boundary lines and matching of fewer symbols. Alterations on air photos should be made clearly and cleanly, and unnecessary symbols and lines deleted.
Terrain polygon boundary lines can be transferred to topographic base maps or to other media by using a stereoplotter (such as a kail plotter) or freehand. The latter method is recommended only if topographic detail and other features sufficient to ensure accurate positioning of boundaries on the map are visible on both air photos and base map.
Minimum Requirements:
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Although a standard terrain legend, with definitions as given in Howes and Kenk (1988), can be applied to any terrain map, more information about a specific map area can be supplied if the legend is tailored to terrain conditions in that area. The chief difference between the standard legend (Fig. 9) and a tailored legend (Fig. 10) is that material and process descriptions in the latter are written so as to apply specifically to the study area. The length of these descriptions will depend on whether or not the map is accompanied by a report. In a tailored legend, unused symbols and their definitions are omitted.
If any modifications to the terrain classification scheme were made in order to meet project objectives, for example, if different types of till were mapped as M1, M2, M3, etc., (e.g., Fig. 3) these symbols must be defined in the legend.
Information from well records, borings or similar sources should be used by a mapper if high quality data are available (Section 5.4). Sites from which data are obtained or where field samples were collected should be marked on the map and numbered, using a scheme that is distinct from that of the field observation sites.