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WorksheetsP 289 | GIS FOR CDRA
Total questions: 15
Worksheet time: 8mins
Geographic representation is often done in two ways:
Discrete fields
Discrete objects
Continuous fields
Continuous Objects
is concerned with the Earth’s surface or near-surface, “what to represent” and “how to represent it”
Discrete fields
Discrete objects
Continuous fields
Continuous Objects
Geographic representation
divides the world into arrays of cells and assigns attributes to the cells
(a)
all lines are captured as points connected by straight lines (polylines), and an area is captured as a series of points or vertices connected by straight lines (polygon) with same starting and end point
(a)
Because maps are flat, some of the simplest projections are made onto geometric shapes that can be flattened without stretching their surfaces. These are called (a) .
Developable surfaces often used in map projection are:
cones
cubes
cylinders
dodecahedron
planes
A (a) systematically projects locations from the surface of a spheroid to representative positions on a flat surface using mathematical algorithms.
The (a) is one of the most common cylindrical projections, and the equator is usually its line of tangency. Meridians are geometrically projected onto the cylindrical surface, and parallels are mathematically projected. This produces graticular angles of 90 degrees.
project map data onto a flat surface touching the globe. A planar projection is also known as an azimuthal projection or a zenithal projection.
(a)
The major components of the graticule are the:
Lines of the Latitude and Longitude
international date line
prime meridian
equator
the north and south poles
_____ values range from 0° to 90°in the northern hemisphere, going from the equator to the North Pole. In the southern hemisphere, they range from 0°to -90°, going from the equator to the South Pole. The angle from a point on the earth’s surface and the equatorial plane, measured from the centre of the sphere
equator
longitude
latitude
the prime meridian
international date line
_____ values range from 0° to 180° in the eastern hemisphere, beginning at the prime meridian in Greenwich, England, and traveling east across Europe, Africa, and Asia. In the western hemisphere, longitude values range from 0° to -180°, starting at the prime meridian and traveling west across the Americas. The angle from a point on the earth’s surface and the prime meridian plane, measured from the center of the sphere.
equator
longitude
latitude
the prime meridian
international date line
The (a) is a specialized application of the transverse Mercator projection that divides the globe into 60 north and south zones, each spanning 6° of longitude. Each zone has its own central meridian. Zones 1N and 1S start at 180° W. The limits of each zone are 84° N and 80° S, with the division between north and south zones occurring at the equator. This projection is used for United States topographic quadrangles, 1:100,000 scale, the large-scale topographic mapping of the former Soviet Union, as well as the Philippines.
_____ involves putting spatial reference information into the raster image in order to make them intelligent
Mapping
Map Projection
Georeferencing
Geographic Projection
_________ formerly Keyhole Earth, is a computer program that renders a 3D representation of Earth based primarily on satellite imagery. The program maps the Earth by superimposing satellite images, aerial photography, and GIS data onto a 3D globe, allowing users to see cities and landscapes from various angles.
Google Maps
Waze
Google Earth
Google 3D
