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Pilots use aeronautical charts based on LCC because a straight line drawn on a Lambert conformal conic projection approximates a great-circle route between endpoints for typical flight distances. The US systems of VFR (visual flight rules) sectional charts and terminal area charts are drafted on the LCC with standard parallels at 33°N and 45 ...
Figure 1. This BLM map depicts the principal meridians and baselines used for surveying states (colored) in the PLSS.. The following are the principal and guide meridians and base lines of the United States, with the year established and a brief summary of what areas' land surveys are based on each.
Meridians are parabolas. Standard parallels at 36°46′N/S; parallels are unequal in spacing and scale; 2:1 aspect. 1949 McBryde–Thomas flat-pole quartic = McBryde–Thomas #4: Pseudocylindrical Equal-area Felix W. McBryde, Paul Thomas Standard parallels at 33°45′N/S; parallels are unequal in spacing and scale; meridians are fourth-order ...
In a conformal projection, parallels and meridians cross rectangularly on the map; but not all maps with this property are conformal. The counterexamples are equirectangular and equal-area cylindrical projections (of normal aspects). These projections expand meridian-wise and parallel-wise by different ratios respectively.
Other meridians are longer than the central meridian and bow outward, away from the central meridian. Pseudocylindrical projections map parallels as straight lines. Along parallels, each point from the surface is mapped at a distance from the central meridian that is proportional to its difference in longitude from the central meridian.
The vertical lines from pole to pole are lines of constant longitude, or meridians. The circles parallel to the equator are lines of constant latitude, or parallels. The graticule shows the latitude and longitude of points on the surface. In this example meridians are spaced at 6° intervals and parallels at 4° intervals.
Strabo, in his Geography (ca 20 AD), states that the maps in Eratosthenes's Geography Book 3 (3rd century BC, now lost) contained lines "drawn from west to east, parallel to the equatorial line" (thus the term parallel) [6] Ptolemy's Geography (ca 150 AD) gives detailed instructions for drawing the parallels and meridians for his two ...
Projected meridians and parallels intersect at right angles. • Projected meridians and parallels intersect at right angles. • The projection is unbounded in the y direction. The poles lie at infinity. • The projection is unbounded in the x direction. The points on the equator at ninety degrees from the central meridian are projected to ...