Below is a glossary of terms used in PDS MAP-A-PLANET, the About MapMaker page, and the related help pages.
Bands: The color images used by PDS MAP-A-PLANET are made of 3 image files (red, green, and blue) which are combined to produce the color map. The color of each pixel is determined by the relative proportion of the red, green, and blue values. Each color image is refered to as a "Band." In the Viking color data, the green band was synthetically generated from the violet and red spectral image observations of the planet.
Contrast: Contrast is the visible difference in brightness from the darkest color to the lightest.
Data Set: PDS MAP-A-PLANET currently uses six Data Sets. These are the Mars color, black & white, and merged color with black & white sets, the Moon Clementine Basemap, the Venus Magellan F-Map, and the Callisto Voyager digital image map.
Grayscale: Grayscale refers to an image which is composed of shades between black and white.
Meridian: Lines of longitude representing north-south direction on a globe or map.
Parallels: A curve formed by the intersection of a ficticious cutting plane parallel to the equatorial plane. A latitude (east-west) line.
Pixel: (Short for picture elements) A pixel is an individual picture element of the two dimensional array that forms the digital image.
Projection: The orderly transfer of positions on the surface of a planet to corresponding points on a flat surface, i.e. a map. Since the surface of a sphere cannot be laid flat on a plane without distortion, the process of transformation requires a degree of approximation and simplification.
Resolution: The number of picture elements used to represent one degree of latitude or longitude on a planet. (Pixels per Degree)
Rhumb line: A line of constant compass direction or bearing.
Scale: The ratio of the sizes of a map and the actual planet it represents. (Kilometers per pixel in PDS MAP-A-PLANET)
Spherical: Having the shape of a round ball.
Zoom: In PDS MAP-A-PLANET, Zoom refers to Resolution.
PDS imaging node