User Manual - pancroma

Euclidean Distance Fraction TM AnalysisAnother powerful technique for conducting land use studies is PANCROMA TMEuclidean Distance Fraction TM analysis. Euclidean distance analysis considersthe target spectrum as a multi dimensional vector. It also considers each pixel inthe data set as a similar vector. It then computes the distance between eachpixel and the target, in the vector sense. Rather than display the entire Euclideandistance plot, Distance Fraction TM analysis allows you to select all pixels within aselected fraction of the difference between the maximum and minimumEuclidean distance. This can result in very selective classifications of landfeatures based on spectral signature matching.Implementing this technique proceeds in a similar fashion to the EuclideanDistance method described in the previous section. For example, to conduct theanalysis using Landsat data, start by opening your multispectral data files. Thenselect ‘Spectral Analysis’ | ‘Landsat Spectral Analyzer’ | ‘Six/Seven DN Bands’ |‘Euclidean Distance’. When the Spectral Criteria form appears, enter your targetspectrum using the slider bars as before. If you have run Spectral Analyzer TM ,your values will of course already be entered. Check the ‘Distance Fraction’check box at the lower right side of the form. This will enable the nine radiobuttons on the Euclidean Distance Fraction panel as shown below.Now select one of the radio buttons. Choosing the top button will display onlythose pixels having the closest Euclidean distance (best match) with the targetspectrum. These will be all pixels within 11% of the total span between themaximum and minimum Euclidean distance. For example, if the maximum256