Geology topics

D.W.G. Arthur

Publications and source records attributed to D.W.G. Arthur.

4 recordsLinked to original sources

USGS1977

Planimetric Martian triangulations

Narrow-angle photographs, which have severe drawbacks for stereophotogrammetry, have advantages for simple plane triangulations. Rectified narrow-angle pictures corrected for map projection effects can be combined in the map plane in relatively accurate planimetric triangulations. Provided the strict precepts of least squares are not followed, these triangulations can incorporate considerable overdetermination without increase in the labor of solving the equations. These plane triangulations have been used successfully in the cartography of Mars and are illustrated here by a triangulation of the environs of the prime Martian landing site.

Photogrammetric Engineering and Remote Sensing↗

USGS1976

Lunar nomenclature: A dissenting note

This note reviews the nature of the traditional (Mädler) lunar nomenclature and the recent developments based on the use of more than 2000 named provinces. It appears that the new nomenclature is less efficient than the old in many cases and may lead to an impossible publication situation. The unnecessary break with the past is especially critized.

Icarus↗

USGS1974

Lunar crater depths from orbiter IV long-focus photographs

The paper presents method and results for the determination of the depths of more than 1900 small lunar craters from measures of shadows on the long-focus pictures obtained by Lunar Orbiter IV. The method for converting the measured shadow length into the true length in nature of the shadow hypotenuse is new and is applicable to other planetary bodies provided comparable spacecraft ephemerides are available. The measures were made with a simple surveyor's plotting scale on the standard Orbiter IV photographic enlargements. The results indicate that the smaller lunar ( D < 30 km) craters are appreciably deeper than is indicated by earlier work using imagery obtained at terrestrial observatories.

Icarus↗

USGS1971

Selenography and selenodesy with Apollo whole-disk lunar photographs I. Selenography

The Apollo whole-disk lunar photographs, with spacecraft lunar nadirs about 70° from the center of mean face, have considerable selenodetic potential provided that the requirements of resolution and precision can be met. Uncertainties in the internal camera geometry degrade the precision and make selenodetic applications doubtful, but selenographic work based on the assumption of a rigorously spherical moon makes lesser demands on the data and is still possible with useful accuracy. The selenographic method is fully developed here and applied to photographs 2505 and 2506 of Apollo 8 to produce a catalog of 635 positions. Of these 206 are farside and extend to 130° East Longitude. A new type of 5-character position word, appropriate for the entire lunar sphere, is used to define sequence in the catalog.

Icarus↗