Image Display Options
Another tool that can be applied to spatial images is the image display option.
Open another spatial analysis of your choosing then click on the image display icon. The following dialogue box will be displayed with the range of values based on your current analysis.
Sometime it could be necessary to display certain very tightly defined areas on your map that have particular climatological characteristics – such as rainfall amounts or temperature ranges. This is often done in threshold studies such as with species diversity.
With your current image, imagine a certain threshold that you wish to display and ‘extract’ the minimum and maximum value for that from your map. Set the number of labels at 1 and then set the minimum and maximum value. Click on OK and look at the display.
You may enhance or place more emphasis on your outputs by changing the display colour.
Left click on the colour currently displayed in the legend and a Modify Palette Entry dialogue box will open.
Click on the colour box and a range of colours will be displayed.
You can also customise your colours and save a customised colour for use later. Click on customised colours to see the full range of options as displayed above. You can change the values in Hue etc to see how a colour is changed.
We provide one example of how this could be used. The following is of precipitation for the USA.
Click on the image display option.
We are interested in the area of the USA that receives between 300 and 700 mm of rainfall a year and we wish to see this in 100 mm intervals.
To do this we redefine the values as follows:
The maximum is 700 and the minimum is 300 i.e. a difference of 400 and we have asked for 4 key labels hence the increment is 100 mm.
NOTE: SOME OF THE VALUES ARE AUTOMATICALLY CALCULATED AS YOU CHANGE ANOTHER. BE SURE TO CLICK IN ALL THE BOXES BEFORE CLICKING OK TO BE SURE THAT ALL THE VALUES ARE DISPLAYED PROPERLY!
The results can be seen below:
For example, see below the same range 300-700 for the year 2100 with a RCP 8.5 scenario, mid sensitivity and Nor_ESM1-M GCM.
Activity: The Image Display tool is extremely powerful and we suggest you spend some time now exploring it further by experimenting with different outputs other than precipitation and comparing different scenarios.
1] Create a scenario (baseline) of your choice.
2] Open the Image Display tool and carve out a particular range to display based on your ‘expert’ knowledge.
3] Alter the colours of the display to emphasise the purpose for your analysis.
4] Open a second image for the same area and variable but with a climate change scenario applied.
NOTE: REMEMBER TO ‘LINK IMAGES’ BEFORE USING THE DISPLAY IMAGE FUNCTION
5] Change the image display to correspond with your first image and compare the results.
6] Do this for different climate variables or try a different study area.