between the DSM and the DTM is calculated to produce a
normal heights raster image. Figure 3 a, b, and c illustrates the
produced LiDAR raster image data (intensity, DSM, and
Normal Height (NH), respectively). Figure 3d represents the
ortho-rectified aerial photos for the study area.
4. RESULTS AND DISCUSSION
A close look to the data provided and the characteristics of the
study area shows that the intensity values of the areas covered
by vegetation (either trees or grass) are higher than those
covered by man-made features (buildings and roads). This is
expected from the reflectance characteristics of vegetation in
Near Infra-Red range. It is also observed that the intensity of the
areas covered by buildings and roads are more homogeneous
than the intensity of trees and grass areas. Moreover, the tree
areas have a larger variation in elevations compared to the
buildings and road areas. Based on the previous observations, it
is noted that intensity data can be effectively used for
distinguishing man-mad features from vegetation fields. The
texture of the intensity can be used for representing the
homogeneity of the land covers, Figure 4 i. The slope of the
elevation data can be used to represent the plane surfaces, such
as buildings and roads, Figure 4 ii, and iii, for the DSM and NH
respectively.
AI
|i
5
Figure 4: Bands created from range and intensity data
1) Intensity Texture, ii) DSM slop, and iii) NH slope
The prepared raster LIDAR data are used individually for the
land cover classification process, Figure 5. The image data
bands used individually are: a) Intensity, b) DSM, and c)
Normal Height. Additionally, six combinations of image bands
are developed to examine the use of the auxiliary data on the
classification results. The auxiliary band combinations are: d)
Intensity and DSM, e) Intensity and Normal Heights (NH), f)
Intensity, DSM, and Intensity Texture, g) Intensity, NH, and
Intensity Texture, h) Intensity, DSM, Intensity Texture, and
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
DSM Slope, and 1) Intensity, NH, Intensity Texture, and NH
Slope. The results of land cover classification of all cases are
shown in Figures 5 se a to 1).
Trees
Buildings
Grass/ Bare Soil
Roads
6) | (k)
Figure 5: Results of Land Cover Classification
The principal components from the 4-bands (Intensity, DSM,
Intensity Texture, and DSM Slope) are generated and classified
(case j). Other principle components from the Intensity, NH,
Intensity Texture, and NH Slope are also generated in order to
test the effect of using the normal height instead of the DSM on