Q

quad-Abbreviated form of quadrangle.

quadrangle-A rectangular, or nearly so, area covered by a map or plat, usually bounded by given meridians of longitude and parallels of latitude. Sometimes shortened to quad; also called quadrangle map. See also standard quadrangle.

quadrangle map-See quadrangle.

quadrangle report-A brief history of the mapping of a specific quadrangle. It accompanies the mapping material through each phase of production, and is filed with the map material. The narrative summary for each operational phase stresses conditions that may affect later phases.

quadrant-1. (mathematics) A sector having

an arc of 90°. 2. (surveying) A surveying or astronomical instrument composed of a graduated arc about 90° in length (180° in range), equipped with a sighting device. The quadrant may be considered a form of sector. Some survey quadrants combine both surveying and astronomical functions.

mile on each side and containing approximately 160 acres; usually identified as the northeast quarter, northwest quarter, southeast quarter, or southwest quarter of a particular section.

quarter-section corner-A corner, at an extremity of a boundary of a quarter section, theoretically located midway between the controlling section corners, or 40 chains from the controlling corner depending on location within the township.

quarter-quarter section-(USPLS) One of the quadrants of a quarter section; normally a quadrangle measuring approximately 4 mile on each side and containing approximately 40 acres; usually identified as the northeast quarter, northwest quarter, southeast quarter, or southwest quarter of a particular quarter section and section.

quarter-quarter section corner-(USPLS) A corner at an extremity of a boundary of a quarter-quarter section; midpoint between the controlling corners on the section or township boundaries. Also called sixteenth-section corner.

quartz pendulum-A pendulum of fused quartz used for for determining the acceleration of gravity. Quartz is employed in the construction because its thermal expansion coefficient is only one-fourth that of invar.

quintant-A sextant having a range of 144°; or an arc of 72°.

R

radar-1. A method, system, or technique of using beamed, reflected, and timed radio waves for detecting, locating, or tracking objects, and for measuring altitude. 2. The electronic equipment or apparatus used to generate, transmit, receive, and usually, to display radio scanning or locating waves; a radar set. An acronym for "radio detection. and ranging."

radar altimeter-An instrument used for determining aircraft flying height above terrain by measurement of time intervals between emission and return of electromagnetic pulses.

radar altitude-The altitude of an aircraft or spacecraft as determined by a radar altimeter; thus, the actual distance from the nearest terrain feature.

radar chart-A chart intended primarily for use with radar, or one suitable for this purpose.

radargrammetry-That branch of photogrammetry utilizing photography of radar images to obtain reliable measurements of natural or manmade features.

radar intelligence map (RIM)-An intermediate element in the process of lightoptical radar simulation and in the production of analytical predictions.

radar intelligence/surface height (RI/SH) overlay-An overlay keyed to the area radar prediction analysis (ARPA) base which depicts radar intelligence and significant reflective surface/height areas. In areas of exceptionally dense culture, an additional overlay depicting surface/height (S/H) areas, only, is a required component of the ARPA. See also area radar prediction analysis (ARPA).

radar map-A map produced through the application of radar techniques.

radar photography-A combination of the photographic process and radar techniques. Electrical impulses are sent out in predetermined directions and the reflected or returned rays are utilized to present images on cathode-ray tubes. Photographs are then taken of the information displayed on the tubes.

radar prediction categories-In the broadest sense, radar prediction is separated into two major categories: experience prediction and analytical prediction.

radar prediction data table (RPDT)—A record in standardized form of radar significant data, derived from the analysis of aerial photographs and intelligence material used in the preparation of the ARPA. See also area radar prediction analysis (ARPA).

radar prediction formats-Radar predictions appear in a wide variety of formats, generally indicative of intended application. The four most common formats are: spot predictions, strip predictions, radar intelligence maps (RIM), and Series 200 Air Target Charts.