Today we will dive a bit into the world of raster again and look at how you can use hill shading to bring out specific features in your raster.
Hill Shading creates a hypothetical illumination of your raster by specifying the position of a hypothetical light, for example, the sun. This position is given by the direction from where the light is coming and the height from where it is coming.
The typical direction is North-West (315 degrees) and a height of 45 degrees. This can be changed to help bring out other features in your raster.
Below is a dynamic GIFF showing the change that different directions can have on your elevation raster. The GIFF starts from a Northern direction, goes via East and South, and ends up coming from a North-Western direction. The GIFF holds 8 different directions in total.
Hi Peter, Another technique with shadow I have always found useful is to use it to highlight the edge of raster cells.
To do this you need to use nearest neighbor interpolation so that there is only a shadow on the edge of cells where there is an abrupt change in data value.
It helps you to see the cell edges and I often use it to understand individual cell values in rasters.
Also, if you have a classified raster where some classifications have the same color, then this can help you identify areas where the cell values change, but the coloration does not. The example picture is Catchment Scale Land Use of Australia 2020. The pink area has two different classification codes which becomes apparent when the shadow shows the cell value transition.