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VRI Data Analysis





4.DBH=Diameter at Breast Height





Emergency Management!

  1. Azimuth:The angular distance to the foot of the vertical circle through a celestial body, measured from north around the observer’s horizon. Azimuth is 0° for an object due north, 90° due east, 180° due south, and 270° due west.
  2. Euclid: also known as Euclid of Alexandria. Was a Greek mathematician. His textbooks were the main teaching tool until the late 19th Century or 20th Century.      Eucilian Distance
    In mathematics, the Euclidean distance or Euclidean metric is the “ordinary” distance between two points that one would measure with a ruler, and is given by the Pythagorean formula
  3. In a right angled triangle:the square of the hypotenuse is equal to the sum of the squares of the other two sides.
  4. What is Map algebra? 
    The Map Algebra language provides building blocks that can be used individually or in conjunction with one another to solve problems. Also
    provides tools to perform operations; conditional statements; and local, focal, zonal, global, and application functions.
  5. Find suitable locations/Identify the best path between places/ Perform statsical analysis on locations/Iterpolate data values for study areas/Clean up data for further analysis/Perform distance and cost analysis.

Buffer Zones

  1. A buffer zone can be put around an airport. Showing noise levels.
  2. A buffer zone can be put around buildings showing fire hazards such as bushes, grass.
  3. A buffer zone can be represented by a Hockey player. Closer you are the more chance of getting body checked.
  4. A buffer zone can cover a Bear den.
  5. A buffer zone can show polution levels from the Pulp Mill. Different levels of smell they emit.

Updated Map



DEM-TIN Definitions.

  1. Resolution: The number of pixels per square inch on computer generated display; the greater  the resolution the clearer the picture.
  2. Discrete Data: Data that can only take certain values. For ex. The number of students in your class.(You can’t have half a student).
  3. Triangulation: A technique  for establishing the distance  between any two points, or the relative postion of two or more points, by using such points as  as vertices of a triangle  or a series of tringles, such that each triangle has a side of know or measurable length(base or baseline) that permits the size of the angles  of the triangle or length  of its other two sides to be established  by observations taken either upon or from the the two ends of the baseline.
  4. Break Lines: A line used to describe the boundary of an imaginary broken-out section or to shorten dimensions that are excessively long. Break lines are wavy and irregular.
  5. Z- Values: Usually the reference to the value of surface height in a DEM.  at a particular X,Y location.
  6. Nodes: Represents change in elevation and direction.
  7. Slope: Is a measurement  of how steap the ground surface is.
  8. Aspect: Orientation of each surface element(direction).
  9. Elevation: Is the height above a fixed reference point.
  10. Tessellated space: No gaps or over lays.

Mo-Town Map.


1. Generalisation is necessary because it simplifies the map. Makes it easier to produce.

2. Maps get more generalised the higher the scale.

3. As scale decreases the features get less details.

4. Simplification features have three dimensions such as length, width, and height. Elements that remain depends on the purpose of the map. And it loses the third dimension.

Selection elements remaining depends on the purpose of the map, and the scale of the map. Higher scale results in fewer details and features.

5.The three types of data classificationa are: Nominal, Ordinal and Interval.


GRASS GIS (Geographic Resources Analysis Support System) is a free, open source geographical information system (GIS) capable of handling raster, topological vector, image processing, and graphic data.

Commonly referred to as GRASS, this is free Geographic Information System (GIS) software used for geospatial data management and analysis, image processing, graphics/maps production, spatial modeling, and visualization. GRASS is currently used in academic and commercial settings around the world, as well as by many governmental agencies and environmental consulting companies. GRASS is an official project of the Open Source Geospatial Foundation.

Originally developed by the U.S. Army Construction Engineering Research Laboratories, GRASS (Geographic Resources Analysis Support System) is a raster/vector GIS, image processing system, and graphics production system. GRASS contains over 350 programs and tools to render maps and images on monitor and paper; manipulate raster, vector, and sites data; process multi spectral image data; and create, manage, and store spatial data. GRASS uses both an intuitive windows interface as well as command line syntax for ease of operations. GRASS can interface with commercial printers, plotters, digitizers, and databases to develop new data as well as manage existing data.