8.7. First and Second Vertical Derivatives

First vertical derivative images can be created using the EnMap Box plugin and can be downloaded from this link. This plugin has been designed to cater for a new satellite that was launched in 2022 and has a large variety of tools for remote sensing data including filtering.

When the plugin is installed it puts and additional link in the Processing Toolbox.

The Spatial Prewitt filter creates a first vertical derivative (1vd) image, the Spatial Laplace filter creates a second vertical derivative (2vd) image and the Spatial Gaussian Gradient Magnitude filter creates a type of analytical signal image.

Clipping of the resultant images may be required and set the background with no data to zero or -99999 so it can be set to transparent.

Note also when creating images for use in MapInfo, create ERMapper ers grid files.