GEOB 270 Lecture Notes - Lecture 6: Ecef, Developable Surface, Cartesian Coordinate System
25 Dec 2016
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Why do projections matter: different projections = different sizes and different land positioning, each projection highlights certain features (very accurate) and downplays other features (less accurate) What should be preserved and what should be distorted. Spatial reference system: key to gis, allows the accurate location of places in space, and comparing relative locations, 3 types of reference. Involves picking certain points of reference: equator: only line of latitude that is a great circle (goes through center of the earth, 1884: at international meridian conference, observatory of. Greenwich in great britain was adopted as official prime meridian. Meridians: zero point in longitude: there are multiple prime meridians. Projected coordinate systems(pcs) any coordinated system designed for flat surfaces. Cartesian coordinate system: two axes: x coordinate for east-west, y coordinate for north-south. Location of geographic objects = relative to origin. Coordinate systems designed for spatial data: pro(cid:448)ide (cid:272)o(cid:373)(cid:373)o(cid:374) (cid:271)asis for (cid:272)o(cid:373)(cid:373)u(cid:374)i(cid:272)atio(cid:374) a(cid:271)out parti(cid:272)ular pla(cid:272)e or area o(cid:374) earth(cid:859)s surface.
