Sunday, September 13, 2015

GIS - objective questions


  • A map is a/an MODEL/ABSTRACTION of the real world
  • A map legend links ATTRIBUTES to geographic information
  • SPATIAL DATA is always graphical
  • Attributes are also called ASPATIAL data or NON-SPATIAL data
  • EASTINGS refer to X-coordinate
  • NORTHINGS refer to Y-coordinate
  • POINT is a single location in space
  • Areas are described by A CLOSED STRING OF SPATIAL COORDINATES
  • The manner in which ENTITIES or geographical features are represented on a map is DEPENDENT ON SCALE
  • LABELS distinguish geographic features of the same type
  • Every feature on the Earth is represented on a map using a SYMBOL
  • A small scale map covers a LARGE area
  • A DATABASE is a repository capable of storing large amounts of data
  • CARTOGRAPHY is the art and science of making maps
  • As scale decreases, size of the features may decrease causing:
        • DISAPPEARANCE OF FEATURES
        • REPRESENTATION OF FEATURES MAY CHANGE 
        • FEATURES MAY CHANGE SHAPE 
        • SOME FEATURES MAY APPEAR
  • AZIMUTHAL projections are also called planar projections
  • Scale factor is a ratio of ACTUAL SCALE to PRINCIPAL SCALE
  • All geographic features are in TWO tangible forms
  • In any projection, the parallel on the development surface that maintains true scale is called STANDARD PARALLEL
  • CONFORMAL projections are used for NAVIGATION purposes requiring accurate directions
  • Conformal projections are also called ORTHOMORPHIC projections
  • DATUM is a set of reference values that serve as a reference for mapping
  • GIS is primarily a DECISION SUPPORT SOFTWARE within a SPATIAL framework
  • A topographic map is a COMPOSITE of different kinds of maps
  • In a projection, distortion is least when the map shows SMALL areas and maximum when the map shows LARGE areas
  • Representative fraction for reference globe is called PRINCIPAL SCALE
  • Principal scale is the ratio of RADIUS OF EARTH to RADIUS OF GLOBE
  • Scale factor is the ratio of ACTUAL SCALE to PRINCIPAL SCALE
  • The two tangible forms in which all geographic features exist are DISCRETE and CONTINUOUS
  • Different kinds of information that are stored in various ways is called a THEME
  • Difference in elevation of an area between tops of hills and bottoms of valleys is known as RELIEF of the terrain
  • A point of known elevation and position is indicated on a map by the letters B.M. meaning BENCH MARK with altitude given to the nearest foot
  • CONTOURS represent the third dimension on a map
  • The difference in elevation represented by adjacent contour lines is termed as CONTOUR INTERVAL
  • The art and science of map making is called CARTOGRAPHY
  • Lines of latitude are called PARALLELS and lines of longitude are called MERIDIANS
  • A cylindrical projection yields a RECTANGULAR graticule whereas a conic projection yields a FAN shaped graticule
  • CONIC projections are suited to map areas having EAST-WEST extents
  • TRANSVERSE MERCATOR projection is suited to map areas with NORTH-SOUTH extents
  • The three important components of GIS are:
        • COMPUTER HARDWARE
        • SOFTWARE APPLICATION MODULES and
        • ORGANIZATION
  • Three popular GIS software application packages along with their vendors are:
        • MGE/MGA system           -           INTERGRAPH CORPORATION
        • ARC/INFO                        -           ESRI
        • SPANS                              -            TYDAC
  • GIS uses a database approach because of:
        • CONVENIENCE
        • REDUCED DATA REDUNDANCY
        • STANDARDIZATION &
        • SHAREABILITY
  • Output from a GIS is normally:
        • MAP
        • TABULAR DATA or
        • REPORTS
  • POINT is the basic building block from which all spatial entities are constructed
  • A closed ring of coordinate pairs defines the boundary of a POLYGON/AREA
  • TOPOLOGY is concerned with connectivity between entities
  • The three elements of topology are:
        • ADJACENCY
        • CONTAINMENT and
        • CONNECTIVITY
  • The four prominent applications of remote sensing and GIS in agriculture are:
        • CROP HEALTH
        • PRECISION AGRICULTURE
        • COMPLIANCE MAPPING &
        • YIELD ESTIMATION