Practical Manual - Malareo

Select the Identify features tool and select a
number of pixels (one at a time around the
continent.) An Identify results window pops
up and shows the value at each point (chosen
pixel).
To Change the display to enable you to see
differences right click on the raster_cases
layer name in the map legend. A context
window opens. Select Stretch using current
extent. (This performs a contrast stretch
using the minimum and maximum values of
the layer).
This illustrates that although the data is in raster format it is
very similar to the vector layer showing the cases of malaria
present in each country. It just has a very blocky pixilated
appearance. Verify the data is similar. To do this turn the
Malaria cases back on and highlight the layer. Then use the
identify features tool. By changing which layer is highlighted
in the map legend the identify features tool returns the value
for that layer.
Can you answer this Question
How many cases did Mozambique have per 100 000 people in
2008________________________________________
Add the Tiff image Africa_150m_earthsat.tiff to your view and move it to the
bottom of the map legend. You will use this layer in the visibility portion of the
practical
Removing layers
There are a number of ways of removing layers. The first is to use the Layer
Menu and select remove layer(s). This will remove the highlighted layer(s) in
the Map legend. To select more than one layer at a time in the map legend
hold down shift and left click on multiple layers.
The second way of removing layers, which you will undertake is to right click
on the layer raster_cases in the map legend. Ensure that only the raster_cases
QGIS for Malaria Page 9