Geographic Information Systems

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Geographic Information Systems

• Geography 1050

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What is a GIS?

• A Geographic Information System (GIS) is a system
  of computer software, hardware and data, and
  personnel to help manipulate, analyze and present
  information that is tied to a spatial location.
• Spatial location usually a geographic location
• System linking software, hardware, and data
• Personnel a thinking explorer who is key to the
  power of a GIS

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What is a GIS?

• A method to visualize, manipulate, analyze, and
  display spatial data
• Smart Maps linking a database to a map

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Data for GIS Application

• Digitized and scanned maps
• Databases - table of data
• Field sampling
• Remote sensing and aerial photographs

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A database - not easy to interpret
Population density in the US
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Visual analysis of dataPicture is worth a
thousand words
Population density in the US
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Different data layers combine
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Maps and databases are Interactive

• GIS User
• asks questions
• sorts and combines data
• looks for patterns and connection

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Two ways to display spatial data

• Raster - Grid
• pixels
• a location and value
• satellite images and aerial photographs are in
  this format
• Vector - Linear
• points, lines, and polygons (shapes)
• feature (house, road, lake, etc.) and attributes
  (size, type, length, etc.)

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Some ways Geographic Information Systems are used

• Emergency Services - Fire and Police
• Environmental - monitoring and modeling
• Business - site location, delivery systems
• Industry - transportation, communications,
  mining, pipelines
• Government - local, provincial, federal,
  military
• Education - research, teaching tool,
  administration

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CASE STUDY- GIS and Aquaculture Soft-Shell Clam
Site Assessment, Burgeo, NL

• evaluation of the viability of the soft-shell
  clam resource
• GIS technology was applied to collected data to
  map and analyze
• physical site characteristics and landuse
• water quality
• the soft-shell clam resource.

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CASE STUDY- GIS and Aquaculture

• study area divided in a series of
• 100 m x 100 m grid cells.
• Field survey data included
• clam biology (length and width and weight)
• hydrographic data (water depth, current speed and
  direction, bottom substrate, tidal data,
  rainfall),
• water quality data (fecal coliform, salinity,
  temperature)
• land use data (cottage locations).

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CASE STUDY- GIS and Aquaculture
Study area, survey grid and water monitoring
locations
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CASE STUDY- GIS and Aquaculture
Water Quality

• Contamination by fecal coliform a concern becaue
  of nearby cottages
• If density exceeds 13.99MPN/100ml harvesting in
  the area is not permitted
• During the majority of the sampling period the
  densities were at 1.9 MPN/100ml
• Following extended rainfall event the fecal
  coliform densities ranged from 17 to 920 MPN/100ml

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CASE STUDY- GIS and Aquaculture Water Quality
Time Series maps of fecal coliform
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CASE STUDY- GIS and Aquaculture
Water Quality

• Clams need salinities of at least 5 parts per
  thousand (ppt) to survive
• Salinity in study area fell below 5ppt during
  rainfall event
• Fecal coliform densities and salinities returned
  to normal more quickly in Big Barasway than in
  Indian Hole and Little Barasway
• Big Barasway flushes faster and therefore this
  area could be seeded with clams from Indian Hole
  and Little Barasway

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CASE STUDY- GIS and Aquaculture
Soft-Shell Clam Database and Aquaculture
Management

• Clam densities of different size classes for
  each grid cell were calculated and mapped
• Recruit class (clams with a length between 50
  and 63.5mm) represents the market clam population
  
• A grid cell is economically viable only if the
  recruit clam density is 10/m sq.

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CASE STUDY- GIS and AquacultureSoft-Shell Clam
Database
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CASE STUDY- GIS and Aquaculture
Aquaculture Management

• Mature clam densities of 161 to 269/m sq. are
  acceptable for good growth
• Densities higher than 269/m sq. can impede
  growth because of competition for food and space
• When the density of mature clams exceeds 269/m
  sq. the area should be culled

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CASE STUDY- GIS and Aquaculture
Harvesting Plan

• GIS is able to identify areas of no harvesting,
  harvesting only, culling only, and combined
  harvesting and culling.
• Criteria for harvesting
• density of recruit clams gt 10/m sq.
• Criteria for culling
• density of mature clams gt 269/m sq.

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CASE STUDY- GIS and Aquaculture
Harvesting Plan