GIS Flashcards
It combines location and information about the location
Geographic Information System (GIS)
Ability to analyze information
Geographic Information System (GIS)
Analyze as many layers of information at once
Geographic Information System (GIS)
Can overlay different spatial information at once
Geographic Information System (GIS)
Information associated with underlying geography, or description of location
Spatial Information
science that deals with the construction, use, and principles behind maps and map use
Cartography
imaginary lines that runs horizontally
Latitude
________________ are numbered from 0 to 90 north and south
Degrees latitude
The ______________ is the imaginary line that divides the north and south hemisphere
equator
also known as parallels since they are parallel and are equal distant from each other (69 miles or 111km apart)
Latitude
Imaginary lines that runs vertically and also known as meridians
Longitude
They converge at the poles and are widest at the equator (69miles or 111 km apart)
Longitude
0 degree refers to ____________ located at Greenwich England and continues 180 degrees east and west where they meet and form the International Date line in the Pacific Ocean
Prime Meridian
is the key to read a map
Map Legend
It provides essential information for the map reader
Map Legend
Ratio between distance on a paper map and distance of the same stretch in actual terrain
Map Scale
The accuracy with which a given map scale can depict the location and shape of map features
Resolution
The ______________ the map scale, the higher the possible resolution
smaller
plays a large role in GIS especially in raster - based modelling
Resolution
the minimum size of objects that can be detected by a sensor system
Spatial Resolution
used to portray all or part of the round earth (3D) on a flat surface (2D) map
Map Projection
All map projections _________ the surface in some fashion
Distort
A map or parts of a map can show one or more, but never all of the following:
- True Directions
- True Distances
- True Areas
- True Shapes
Longitudes equally spaced
Cylindrical Projection
Latitudes unequally spaced
Cylindrical Projection
Scales is true along equator
Cylindrical Projection
Shape and scale distortions increase near poles
Cylindrical Projection
Shows true direction
Cylindrical Projection
Universal Traverse Mercator
Cylindrical Projection
Result from projecting a spherical surface onto a cone
Conic Projection
Best for mid-latitudes with an East- West orientation like Canada
Conic Projection
Result from projecting a spherical surface onto a plane
Azimuthal (Planar) Projection
Best for Polar or Circular Regions
Azimuthal (Planar) Projection
Direction always true from center
Azimuthal (Planar) Projection
enable geographic datasets to use common locations for integration
Coordinate System
used to represent the locations of geographic features, imagery, and observations such as GPS locations within a common geographic framework
Reference System
a combination of factors; ellipsoid, geoid, datum, coordinate system and projection that identify a point on a sphere and on a two dimensional representation of the sphere
Spatial Reference Framework
the science of measuring the earth
Geodesy
the science of identifying and measuring specific locations on the earth
Surveying
a mathematical model of the size and shape of the earth
Ellipsoid
slightly non-spherical object, but not necessarily mathematically definable
Spheroid
a theoretical surface generally defined as mean sea level
Geoid
used as the basis for a vertical datum and as a reference for a horizontal datum
Geoid
a spheroid used as an (X,Y) reference to all points on the real globe
Horizontal Datum
level surface to which heights (elevation) are referenced
Vertical Datum
A global or spherical coordinate system such as latitude - longitude. These are often referred to as ______________________
Geographic Coordinate Systems
based on a map projection such as transverse Mercator, which provide various mechanisms to project maps of the earth’s spherical surface onto a two-dimensional Cartesian Coordinate Plane
Projected coordinate system