ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
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Articles | Volume V-3-2021
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., V-3-2021, 159–165, 2021
https://doi.org/10.5194/isprs-annals-V-3-2021-159-2021
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., V-3-2021, 159–165, 2021
https://doi.org/10.5194/isprs-annals-V-3-2021-159-2021

  17 Jun 2021

17 Jun 2021

POSITIVE AND NEGATIVE ROUGHNESS ACCORDING TO LOCAL DIFFERENCES BETWEEN DEM SURFACE AND 3D REFERENCE PLANES

J.-F. Parrot1 and C. Ramírez-Núñez2 J.-F. Parrot and C. Ramírez-Núñez
  • 1Laboratorio de Análisis Geoespacial (LAGE), Instituto de Geografía, UNAM, Ciudad de México, México
  • 2ENCiT, UNAM, Ciudad de México, México

Keywords: local roughness, global roughness, Digital Elevation Models, tri-dimensional plane of reference, reference plane orientation

Abstract. The irregularities of the earth’s surface are quantified by means of roughness measurements using Digital Elevation Models (DEM’s). This article presents a roughness measurement method that is based on the calculation of the difference of altitude existing between a plane passing through the centre of a moving window and the altitude of the DEM surface inside this window. This method differs from the measure of the standard deviation and best fit plane, in the sense that it considers all difference values, positives or negatives. The measurement is done in a 3 × 3 or a 5 × 5 moving window and contemplates inside this window the plane which passes through the centre of the window and the highest pixel located in the border or perimeter of this window. According to the 3D configuration of the DEM surface inside the moving window, the sum of all the differences is positive or negative, allowing to discriminate the local morphology independently of the global roughness. The roughness variable which distinguishes negative and positive values allows to classify accurately landscape units such as watersheds, riverbeds, volcanic assemblages as well as landforms associated with tectonic structures.