GE3502GE5502 Geographic and Land Information Systems

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GE3502/GE5502Geographic and LandInformation
Systems
Discussion of Assignment 1
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Outline

• Doing a GIS analysis
• Discussion of Assignment 1
• Riparian and mangrove vegetation
• The database
• Question 1
• Question 2
• Question 3
• Discussion
• Notes for assignment

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Steps in Beginning a GIS project.

• Keep it simple. Unnecessarily complex processes
  increases the likelihood of error, and geographic
  information can be very expensive.
• Read documentation
• Use existing data (cheaper)
• Plan ahead. Get your flowcharts and data sources
  sorted.
• Keep good records (source data and analysis
  performed for each step)
• Check results. ie. are they logical? Do this
  prior to next step.
• Consult with experts.

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1. Overall Structure of the Report

• This is a scientific report, and as such requires
  a traditional scientific report structure as
  follows (this is modified in part to allow for
  the presentation of maps)
• Title
• Must be brief (lt 20 words) and allude to, your
  MAIN MESSAGE!
• Introduction
• Background information
• Scope and focus of study
• Logical framework of report
• Usually written last
• Specific aims and objectives

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• Methods
• Important in quantitative studies
• Includes study design, research concepts and
  techniques
• Describes data collection and analysis
• Your Design Outline is included in the methods.
• Results
• Usually divided into sub-sections
• Contains facts and refers to examples, tables,
  graphs, diagrams, etc.
• Is not the place to discuss results - just
  present them
• Tables, graphs and maps should be placed here.

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• Discussion, Conclusions and Recommendations
• In large reports these are usually separate
  sections
• Interpret data presented in results
• Appropriate time for speculation or presenting a
  new hypothesis
• Provides rationale basis for recommendations
• Conclusions should be forcefully and
  convincingly expressed
• Appendices
• Extra summary data that is relevant, but not
  directly related to results

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Assignment 1

• Riparian and mangrove vegetation
• Riparian vegetation is the thicker vegetation
  found along watercourses.
• Natural vegetation is often used as a filter or
  buffer
• It can control the spread of contaminants into
  waterways.

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• There are differing species and buffer width
  ratios that can be introduced along drainage
  lines to control surface runoff.
• These depend on the species of vegetation in
  buffer
• and their capacity to absorb N and P nutrients
  and the volume of runoff from surrounding
  catchments
• which depend on type of land use and its area.

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• The Database 3 vector coverages
• Landuse Subcatch
  Drainage

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The Trinity Inlet catchment area

• The catchment is divided into 18 sub-catchments
• The inner boundaries of sub catchments have been
  defined as where the mangroves start (the
  intertidal area).

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• Question 1 The area of each landuse that occurs
  within each sub-catchment
• Need to identify the area of landuse types within
  individual sub-catchments

• e.g. for subcatch-id 10
• area of forest ? ha
• area of agriculture ? ha

Forest
Agriculture
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• Question 2 The proportion of land in each
  sub-catchment that can potentially function as a
  drainage system
• Major means by which contaminants can get into
  Trinity Inlet is by entering creeks and drains.
• Assume land, say100 m, either side of drainage
  lines can act as a runoff area carrying nutrients
  into Trinity Inlet.

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The drainage area
e.g. for subcatch-id 10 of drainage area ?
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• Question 3 The potential organic contaminant
  loadings of the drainage system within each
  sub-catchment
• Need to identify landuse within each drainage
  system.
• Use results from above and Table 1 (page 43 of
  workbook) to calculate the contaminant loadings
  within each subcatchment.

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The drainage system

• e.g. for drainage system of
• subcatch-id 10
• area of agriculture ? ha
• nitrogen loading area x 12.5 kg/yr

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Outputs required to answer questions

• Largely up to you. Use imagination, and refer to
  the literature to see how others display similar
  types of data.
• Q.1. Current landuses and proportions of each
  that occur within any sub-catchment
• Q.2.Proportion of each catchment functioning as a
  drainage system
• Possible Visual outputs.
• Statistical summary of proportional land uses and
  their relative organic contaminant loadings (N
  and P) within each catchment.
• Map showing the landuse practices and
  subcatchments
• Statistical summary and map of drainage buffers
  within subcatchments

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• Q.3. The potential organic loadings of the
  drainage system in each sub-catchment.
• Graph or table of landuse within the drainage
  buffers.
• Table of organic loadings within each
  sub-catchment
• Map of subcatchments with rankings
• EXCEL or SPSS to produce histograms and ArcGIS to
  produce map.

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7. Procedures for Undertaking Analyses

• ???? (Have a think about this).

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Discussion topics

• What is missing? What is not entirely
  appropriate? How could this project be improved
  with the use of other data sources?
• Examples of missing data
• Rainfall, and seasonal changes in land use type
  and cover (remote sensing is an important data
  source for land use change).
• Soil type (infiltration characteristics and
  erodibility both of which influence surface
  run-off).
• Slope and slope length (gravity). Catchment size
  and shape (drainage area and time of
  concentration). Terrain modelling (TIN)
• Fertilizer and pesticide applications.
• Investment. Tenure

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Discussion (cont.)

• There is enough scope in this exercise for you
  emphasise either
• GIS and decision-making/ risk assessment, or
• GIS and terrain modelling (earth surface
  processes)
• GIS and environmental management (riparian
  vegetation and land use)

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NOTES

• All spatial analysis must be done within the
  ArcGIS or ArcInfo environment
• Report must include a cartographic model of steps
  taken to answer each question
• The assignments are to be completed individually,
  group work is not allowed
• The course has already covered all the GIS you
  need to know to complete the assignment,
  therefore minimal help with the answers will be
  provided during tutorials

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Cartographic Models
DeMers, 2000 Chapter 13
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