Automated Cartographic Sounding Selection

Soundings on nautical charts provide information about the shape of the ocean bottom between chart depth curves. A single chart may have thousands of soundings posted on it. Today, the selection of soundings for chart display is usually performed manually. This paper describes a computer system which automatically selects soundings for display on a nautical chart. The system is composed of several computer programs which make use of a grid-based model of the ocean bottom. The ocean bottom model is initialized by gridding the depth curves and shoreline displayed on the nautical chart. Soundings which deviate from the ocean bottom model are selected for chart display. Based on initial results obtained from testing these programs, it appears that a significant part of the work required to select soundings for chart display can be automated

Imposing Geologic Interpretations on Computer-Generated Contours Using Distance Transformation

Developing practical computer programs to impose geologic interpretations an computer-generated contours has proven to be difficult. Today, complex data transformation, tedious contour editing, or both are used to achieve that goal. This paper introduces a new program for incorporating high-quality geologic interpretations into computer contouring. The program is robust, easy to implement, and easy to explain to potential users. The computational complexity of the program is high, but the results are worth the price. KEY WORDS: surface modeling, gridding, directional bias, anisotropy