Abstract
Photogrammctric mapping methods (Dueholm, 1979; Jepsen & Dueholm, 1978; Pedersen, 1981) are widely used by the Geological Survey of Greenland (GGU). However, until now it has only been possible to use vertical aerial photographs taken with large frame photogrammetric cameras. As a major part af the geology in Greenland is exposed on steep mountain sides. there are many afcas that e(]llllot be rnappcd from vertical aerial pl1otographs. In 1983 a research projccl was set up to invcstigate phologrammetric mapping using commerci ally available oblique aeria! photographs, as well as terrestriaJ photographs taken by geologists with ordinary 24/36 mm cameras (fig. 1). A new type of photogrammetric instrument, the Kern DSR11/GP1 AnalyticaI Plotter, was procured for this and other projects. Here we present results and experience from the first successful mapping in Greenland with an ordinary 24/36 mm camera.
Highlights
Photogrammctric mapping Illcthods (Ducholm, IY79; Jepsen & Ducholm, 1978; Pedersen, 1(81) are widdy used by (he Geological Survey of Green/and (GGU)
Scveral circumstances renctered the Store Malene arca suitahle for an experiment in handheld tcrrcstrial geologi cal photograrnmetry: tbe gaod quality and appropriatc seale af the existing vertical aecial photographs. the rnany geological features visible on the mountain faces, the need to fiJI the geologiea! gaps Jeft after mapping from the vertica! photographs, and the good accessibility af
The photographs were taken in 1985 by a geologist from a rubber dingby in Kobbefjord sailing along the coastline at a distance of about 1.5 km from the outerops af interest
Summary
Some af the minerJlised horizons and cross-cutting pegmatites erop out on steep Illountain sides racing Kobbefjord to the south-east The coverage af these mountain f"ces is very poer on the venical photogrllpns, due to an unfavourab\e position af the TOute af flying. The wide angle lens facilitated the taking of parallel photographs: slanting lines immediately appeared wilen the camera was nol directed perpendicularly to the mountain face. Il is alsa impartant that the mOllntain side fills out the frame as much as possibie to help the orientaIion af the photographs in the analyticai plotter. The latter demand, combined with the choice of a wide angle lens gives practical problems in this praject.
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