GIS 201 Chapter 11

360

-180 to 180 degrees

-90 at the south pole to 90 at the north pole.

An oblong sphere with a major and minor axis; AKA ellipsoid.

The measurement of the earth's radius with respect to a datum.

GRS_1980.

Shape or direction at the expense of area and distance.

Area or distance at the expense of direction and shape.

By placing a plane tangent or secant to the sphere.

Area or distance at the expense of direction or shape.

The y=0 line.

A 6-line text file holding the parameters needed to georeference the raster.

Root Mean Square Error; after rectification of a raster, there may still be offsets between the two sets of ground control points, and this RMSE serves as a measure of the accuracy of the transformation.

Rasters containing categorical data should be resampled w/the nearest neighbor method; continuous rasters should be resampled with the bilinear method.

60

• Lambert Conformal Conic (for east-west zones)
• Transverse Mercator (for north-south zones)
• Oblique Mercator

The range of allowable x-y values that can be stored in a feature class.

The range of the x-y coordinates of the features actually in the feature class.

Acts on the x-y coordinates of a layer and converts them to a different coordinate system, producing a new feature class and leaving the original feature class unchanged. Should be used only on layers with correct coordinate system definitions.

Changes only the coordinate system label of the feature class, without affecting the coordinates inside. Should only be used on on a data set that has an unknown coordinate system or on a data set that was previously mislabeled and needs to be fixed.