Geography Reference
In-Depth Information
Complex models of terrain features can be found in geospatial databases in
which all features have given properties (shape, size, location, thematic and time
properties, etc.). Additional properties can be derived, for example a slope from
digital elevation model. They are two different views on digital features and their
properties—with or without consideration data quality and mainly their certainty or
uncertainty. For example position of a given feature saved in the geospatial
database is determined by its coordinates. But its real position in the terrain may
be different depending on its natural properties. Building footprints can be mea-
sured with an accuracy of centimeters, but borders of various types of soils are quite
indeterminate. If uncertainty of feature properties is not considered in spatial
analyses, the final results can be a bit out of reality and using them in decision
making process may cause difficulties in the future. To decrease the possibility of a
wrong decision, the uncertainty of digital features must be taken into account.
Application of fuzzy logic in spatial analyses is one possible and quite frequent
way and it is possible to find many examples of using general fuzzy logic (Zadeh
1965
; Ahmad and Kharal
2009
; Sunila and Hottanainen
2004
), or its application in
decision making processes (Di Martino and Sessa
2011
;D
Amico et al.
2013
;
Kainz
2007
; Talhofer et al.
2012
). The following text presents two examples of
fuzzy logic application in spatial analyses used in the armed forces. ArcGIS 10 was
used for both examples (ESRI
2013
).
'
Analysis of Potential Helicopter Landing Sites
To carry out an analysis of locations suitable for landing of a helicopter in a given
area (Helicopter Landing Sites—HLS), both natural and man-made terrain features
that can represent obstacles have to be determined. There are features that can act as
obstacles due to their height such as forests, power lines, or communication towers.
Other features can impede landing by their nature such as vineyards, lakes, or
swamps. All these features can be found in geospatial databases and they can be
classed to categories as follows (Kovarik
2011
):
Vegetation:
forest, wood strip, nursery, orchard, vineyard, hop-garden, reed-
grass
Water:
lake, pond, reservoir, river, stream, canal, ditch, swamp, aqueduct, water
tower
Transportation:
road, railroad, aerial cableway
Utilities:
pipeline, power transmission line
Terrain:
rocks, cliffs, crevasse, depression, fault, landslide, karst
Built-up areas:
settlement
Other objects:
chimney, cooling tower, power station, transformer yard, oil rig,
tower, communication tower, windmill, cemetery
The physical model of interaction between helicopter and surrounding landscape
of HLS is described in STANAG 2999 (
2012
). This document does not specify the
