Quadrat selection is a common manual process in archaeology, biology, geology, and other fields whereby some projectively distorted square in a field-acquired image is normalized to allow for further quantifying actions. For example, this tool was developed for coral surveillance efforts, where benthic abundance estimates were found based on the segmentation of a collection of projectively normalized quadrat images.
This tool is interactive and easy to use. You click on the four corners of your quadrat in an image and are presented with the prospective quadrat. As you click and drag the corners you are shown the new quadrat. When satisfied, you may save the quadrat.