[Music playing]

[Screen shows a blue sky with clouds. Text on the screen reads, ‘Curriculum Secondary Learners – HSIE. Teaching geographical skills series. Other graphs. Presented by Melissa Ellis.’]

Melissa Ellis

Hello. In this episode, we're going to review some other common graphs used in geography.

[Presenter is standing in front of a decorative background. In the bottom right-hand corner of the screen, the text reads, ‘Melissa Ellis. HSIE Curriculum Support Project Officer.’]

Scatter graphs. Scatter graphs show the relationship between 2 variables. For example, soil erosion and vegetation cover. Just take a moment to think about the relationship between erosion and vegetation. I'd suggest that you are likely to see less erosion where you find more vegetation.

Here is an image of a scatter graph showing erosion and vegetation.

[Text on screen reads, ‘Scatter graph’. The screen shows an image of a graph with gridlines on a blue background. The horizontal axis reads, ‘Soil erosion. Ton/ha/year’. The vertical axis reads, ‘Vegetation cover’. Red dots begin appearing along the top-left area of the graph beside the vertical axis. The dots then begin appearing in greater numbers and closer together as they travel down towards the bottom-left corner of the graph. A white line begins to appear and follows the direction of the dots. The red dots continue to appear along the bottom of the page on the horizontal axis. They are close together at first, but become spread out as the line follows the dots further along the axis towards the right-hand side of the graph.]

See the relationship you can observe when using this type of graph.

[Text on screen reads, ‘Low vegetation cover = high erosion’. An arrow points to a red dot at the top of the vertical axis where erosion is high and the vegetation cover is low.]

Cumulative bar graphs. Cumulative bar graphs show layers of data and allow you to see the proportion that makes the total. The difference between the points on adjacent lines gives the actual values.

[Text on screen reads, ‘Cumulative bar graph’. The screen shows 3 different-sized bars, each with 4 different coloured parts that are also different lengths. The colours range from light blue at the top, followed by red, green and purple at the bottom of the bars.]

To show you this, the areas between the lines are usually shaded or coloured. And there is an accompanying key.

[Screen shows a purple dotted line and text that reads, ‘Plastic bags’. These are pointing to the purple part of the columns. Text on the screen shows that the green columns represent plastic bottles, the red columns represent food containers and the light blue columns represent wrappers.]

The rules for cumulative line graphs include the highest line shows the overall total, each line underneath shows the total of one of the parts that goes to make up the overall total.

[Screen shows a white line appear along the top of the highest column. Text on the screen reads, ‘35kg’. The light blue part of the column reads, ‘4kg’. The red part of the column reads, ‘15kg’. The green part of the column reads, ‘6kg’ and the purple part reads, ‘9kg’.]

When reading the graph, take each proportion and measure it as its own.

[Screen zooms in to the red part of the column graph, while the other parts of the graph fade away. A red line appears along the right edge of the column.]

Divergence bar charts. Divergence bar charts are used to show how measurements vary above and below an average, or some other value. Here we have an example of a divergence bar chart. Note, positive above the line and negative below the line.

[Text on screen reads, ‘Divergence bar chart’. On an imaginary horizontal line in the centre of the screen, columns in shades of blue appear, travelling upwards. Columns in different shades of red appear, travelling downwards. The screen shows an arrow pointing to the blue columns with the word, ‘Positive’. The screen shows an arrow pointing to the red columns with the word, ‘Negative’.]

Divergence bar charts are very useful when you want to illustrate change over time.

[Screen zooms into the graph. Years appear at the base of each column along the centre line, spanning from ‘2018’ to ‘2029’.]

Finally, ternary graphs. These graphs show the relationship between three variables.

[Screen reads, ‘Ternary graph’ beside an image of a triangle with irregular shapes inside it. Each of the shapes are different colours. The 3 axes of the triangle are numbered ‘1’, ‘2’ and ‘3’. The edge of each axes is marked with numbers in tens from ‘10’ to ‘100’.]

This type of graph is commonly used to show soil composition at a location. The ternary graph has three axes. The total has to equal 100 to be accurate.

[Each of the irregular shapes inside the triangle become labelled with different types of soil. Each axis is labelled with, ‘clay %’, ‘silt %’ and ‘sand %’. The screen shows a circle appear around all three ‘100’ numbers in each corner of the triangle.]

The trick to reading ternary graphs is remembering the number angle corresponds with the line. Where your three lines meet, your answer will be.

[Screen shows 3 red lines appear from each axis of the triangle and meet in the centre. This area is labelled, ‘foam’.]

Thanks for watching.

[Text on screen reads, ‘Acknowledgements. NSW Geography K-10 syllabus © NSW Education Standards Authority (NESA) for and on behalf of the Crown in right of the State of New South Wales 2015. See the NESA website for additional copyright information. NSW Department of Education Curriculum Secondary Learners. Southern Cross School of Distance Education.’

The screen shows an Indigenous artwork. The artwork features a landscape with native Australian animals. It is titled, ‘Our Country’ by Garry Purchase. The text at the top of the screen reads, ‘Filming of these videos has taken place on Bundjalung land.’ Video concludes by displaying the NSW Government logo.]

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