# Graphical Techniques

We use graphs to identify differences, show/ decribe spatial patterns, identify relationships/ correlations/ anomolies and to classify data.

But what is the value and usefulness of various geographical techniques? Applications/ strengths/ weaknesses etc.

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• Created by: Bethany
• Created on: 08-04-14 17:31
• Graphical Techniques
• Arithmetic Line Graphs
• Practical Applications
• Demographic Transition Model (DMT) to show population change over time
• Can show death rate, birth rate and total population
• Population Change for a specific place e.g. Hull
• Usefulness
• Excellent for showing change over time including trends/ patterns for different data (DMT involves three sets)
• Simple and easy to draw
• Working out the appropriate scale on the x-axis (independant variable) can be difficult.
• Both raw data and transformed data (e.g. % figures) can be plotted.
• Logarithmic Line Graphs
• Practical Applications
• World population growth over time (scale would have to go to 7 billion)
• Hjulstrom Curve
• Usefulness
• Excellent Technique for showing a large spread of data that is difficult to display otherwise
• Can be easily misinterpreted at first glance. Two parallel lines may have very different trends.
• Problems if plotted point crosses area where scale increments change
• Bar charts/ graphs
• Practical Applications
• Average number of people visiting Beverley Town Centre on different days of the week.
• Usefulness
• Very easy to construct quickly
• Easy to interpret
• Can use for raw data and %
• Works less well wih a wide data spread - largest bars are too big or the smallest to small
• Bars can be comparative
• Compound Bar Graph
• Practical Applications
• % breakdown by sector of primary, secondary, tertiary etc. (employment statistics)
• Usefulness
• More visually effective than a number of separate bars.
• Doesn't work as well if bar is divided up into many sections e.g 10+
• Works well with % as all values will add up to 100
• Cross Sections
• Practical Applications
• Profile of a sand dune (psammosere)
• Usefulness
• Give a clear, visual, understanding of relief
• Scale is crucial to prevent the cross section becoming distorted and misleading.
• Kite Diagrams
• Practical Applications
• The % cover of sea couch along a sand dune transect
• Usefulness
• Good way of showing change over distance that is easy to interpret
• Good for simple comparisons of distrabution e.g. plant species types.
• Usefulness
• Useful for data with a directional component
• Can only be used where the scale around the circumference is continuous e.g. bearings
• Practical Applications
• Showing traffic flow over time
• Scattergraphs
• Practical Applications
• % marks in geography and physics.
• Usefulness
• Can only show two data sets
• Easy to see anomolies
• Easy to identify correllations/ relationships
• Ineffecitve with large data spreads
• Can use log scales
• Triangular Graphs
• Usefulness
• Can only work with 3 variables - restictive