Orthographic Plate Carree All circles are same shape and area Shape distortion

Orthographic plate carree all circles are same shape

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Orthographic Plate Carree All circles are same shape and area Shape distortion Notice stretching of meridians so that they can be shown as straight lines.
Azimuthal equidistant Preserves distance and direction pasting through one point
Robinson Preserves a bit of everything
ESRI Virtual Campus, ‘Referencing Data to Real Locations’ Developable surface surface that can be laid flat without any stretching or tearing Plane Cylinder Cone Polar maps in normal (polar) aspect World maps in normal (equatorial) aspect Continental maps mid- latitude in normal (polar) aspect Projection surfaces
Projection surfaces ESRI Virtual Campus, ‘Referencing Data to Real Locations’ Tangent surface touches sphere Secant surface cuts through sphere No distortion at contact points Distortion increases away from contact points
Which projection to use?
Projection Parameters When we define a projection on a map we need to understand the various parameters that are required: Units Scale Scale factor Standard parallels / latitudes Origin False easting/northing Ellipsoid Datum
Projection Parameters Units The unit of measure used for map coordinates e.g., meters, feet, decimal degrees (DD) Many projections (e.g., UTM, Transverse Mercator) are defined for meters only Scale Represents the ratio of a distance on the map to the same distance on the earth e.g., 1:50,000. But: it is not possible to transform a spherical surface to a plane without stretching or shrinking parts of the map and therefore this scale is not constant everywhere Thus, most projections have one or two lines where scale is constant. The map scale at these locations is known as the " principal scale " or " true scale ".