in 9th Inter-
nment, Ann Arbor,
s of Multi-
'erence of the
Aerial
> Sensing for
he Endangered
> of Germany,
STATISTICAL LAND USE DATA BASED ON THE INTERPRETATION OF
AERIAL PHOTOGRAPHS AND SAMPLING METHODS
Heinz Trachsler
Institute for National, Regional an Local Planning,
Swiss Federal Institute of Technology Zurich
1. Introduction
Detailed information about the existing spatial organization
is an important postulate at the beginning of every planning
process. As land use is a significant part of this spatial
organization the planner in-charge also has to collect and
process data of the actual land use. This will be an important
basis for securing a harmonious utilization of the land in
the future (1l).
The main sources for land use data are statistics and thematic
maps. Switzerland, at the moment does not dispose of any large
scale land use maos, the only land use map available has a
scale of 1:500'000 (2) and is therefore not suited for
planning purposes on the local and regional level. Concer-
ning statistical data the situation is also not satisfactory.
The official land use statistic (3) which is published on the
community level is derived from the cadastral survey. This
survey however is not yet accomplished for the whole country
and also has not been updated regularly in the past years.
For this reason the statistical data for many communities are
not up to date anymore and they are not referring to the same
period of time. The land use statistic therefore is only of
limited use for planning purposes, particularly no reliable
figures on changes in land use can be obtained. Due to this
reasons other possibilities for obtaining data on a nationwide
land use inventory are investigated. It is obvious, that the
methods considered will have to be faster and less expensive
than a modification and acceleration of the mentioned
cadastral survey. Collecting the land use information by
visual interpretation of aerial photographs and determining
the surfaces of the various land use categories by sampling
methods turned out to be a realistic approach.
The first part of this paper deals with collecting land use
data by sampling methods. Afterwards different possibilities
for sampling with aerial photographs are presented and finally
test studies with three different methods for data acquisition
are discussed.