MARSDEN chart (Con.) 



Mercator projection 



These squares are systematically 

 numbered to indicate position. Each 

 square may be divided into quarter 

 squares, or into 100 1° subsquares 

 numbered from to 9 9 to give the 

 position to the nearest degree. 



A conformal map projection of the 

 cylindrical type. The equator is 

 represented by a straight line true to 

 scale; the geographic meridians are 

 represented by parallel straight 

 lines perpendicular to the line 

 representing the equator; they are 

 spaced according to their distance 

 apart at the equator. The geographic 

 parallels are represented by a second 

 system of straight lines perpendicular 

 to the family of lines representing 

 the meridians and therefore parallel 

 with the equator. Conf ormability is 

 achieved by mathematical analysis, 

 the spacing of the parallels being 

 increased with increasing distance 

 from the equator to conform with the 

 expanding scale along the parallels 

 resulting from the meridians being 

 represented by parallel lines. Also 

 called equatorial cylindrical 

 orthomorphic map projection. 



Merge 



Meridional part 



To combine two or more sets of items 

 into one, usually in a specified 

 sequence. 



The length of the arc of a meridian 

 between the equator and a given 

 parallel on a Mercator chart, ex- 

 pressed in units of one minute of 

 longitude at the equator. 



Offline 



Pertaining to equipment of devices not 

 under direct control of the central 

 processing unit. 



Online 



Pertaining to equipment or devices 

 under direct control of the central 

 processing unit. 



50 



