Introduction to ILWIS , using data from Kathmandu, Nepal. 1 The exercises in this chapter are modified from the ILWIS Users Guide, by substituting the. ILWIS Academic: user’s guide. R. Nijmeijer, A. de Haas, R.J.J. Dost, P.E. Budde Place of Publication, Enschede. Publisher, ITC, ILWIS. Publication status. Title, {ILWIS Academic user’s guide}. Publication Type, Book. Year of Publication, Authors, Unit Geo Software Development. Number.

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The shadow areas can no be simply depicted as the areas where a change occured: Proceedings of the 5th International Symposium on….

We will use somewhat different classification, which primarily reflects the purpose of the analysis. We recommend somewhat modified list of generic landforms13 see Table 1. Accuracy of topographic maps derived from ers-1 interferometric gukde.

Study area classified into the guire landforms. Reduction of outliers and 3. Landform Description SLOPE PLANC SCI Stream Locations of water accumulation channel and transition; high number of min min avg Valley upstream elements and concave bottom shapes Locations of water run-off; low- Ridge est upstream contributing area and min max min Peak convex shapes Sloping part with generally higher Slope max avg max shape complexity Plain Ter- Flat areas of low relief and low min avg min race shape complexity Pit Conical concave landform avg min min generic landform can be termed: The algorithm is described in more detail by Gorte and Koolhoven [25].


For a given data set of size Nthe bin width W is commonly estimated using the unbiased estimation of the probability density function [36]: No part of this book may be published, reproduced, or stored in a database or retrieval system, in any form or in any way, either mechanically, electronically, by print, photocopy or any other means, without the prior written permission of the authors.

In many cases, however, it can be approximated giide a con- tiguous and smooth surface.

ILWIS 3.0 Academic user’s guide

Imagine a one- dimensional topography with specific number of inflection points7 Fig. Extracting topographic terrain features from elevation maps. In the last step, the existing information on water bodies W bodies is used to adjust the DEM see Eq.

Somewhat more extensive is the LandLord [19], which offers various operations from DEM interpolation to derivation of gradient, aspect, curvatures, specific catchment area, topographic and stream power indices. The latest book is probably the state-of-the-art guice of DTA.

These can be either spatial objects, values or textual strings. Gallant, editors, Terrain Analysis: The vertical precision of the DEM can be compared to the selection of the optimal histogram bin size.


Rule 2 Absolute relief is a measure of the relief significance. From the above-mentioned techniques, laserscanning seems iowis be the most accurate method with the highest sampling density.

ILWIS Academic user’s guide | A Practical Guide to Geostatistical Mapping

Geografiska Annaler, 57A We recommend at least three DEM filtering steps prior to derivation of terrain parameters [27]: You can download the datasets and scripts and see dynamic visaulisations of the error propagation at http: Earth Surface Processes Landforms, Some of jlwis features are shown below. Automated DEM filtering in three steps — change in elevation values.

Study area Baranja hill: Proceedings IEEE, 69 1: The filtering levels and consequent change in the DEM can be seen in Fig. ITC, Enschede, the Netherlands, 2nd edition, Another option is use of the Topoview, the ArcView extension that calculates incoming solar radiation insolation based upon DEMs [26].

Here, the original elevation is compared with the value estimated from the neighbours: The cast-shadow and direct shadow areas can be detected by iteratively inspecting the local slope angle.