4. Test studies carried out
The first three procedures mentioned in chapter 3 have been
used for collecting land use data in various test areas. The
intention of these test studies was to gain information about
the accuracy of these sampling techniques as well as about
the time and costs needed for an extensive survey for a
countrywide statistic. One of the test areas was a community
with a surface of about 600 hectares. It's main use is
agriculture and forestry, residential areas comprise about 4$
of the area under investigation.
The land use classification which has been developed for the
test studies is reflecting the needs of different users of the
statistic (compare table 1), like private and government
planning offices and the Federal Department of Agriculture.
Besides the user's requirements, possibilities and limitations
set by the technique of photo interpretation had also to be
taken in consideration.
For the land use interpretation black and white photographs
with an average scale of 1:24'000 have been used.
Table 1:
Land use classification used for test studies:
Open areas Built up areas
- meadows an cropfields - buildings (residential and
- pastures commercial)
- vineyards - courtyards, gardens
- fruit cultures - industries
- marshes - parks and public grounds
- forests - motorways
- exploitations and - roads
deposits - railways
- uncultivated and
unproductive areas
- lakes
— rivers
4.1 Sampling on a land use map based on aerial photographs
In the first step the aerial photographs are visually inter-
preted under a stereoscope. The various land use categories
are delineated on the photo and then transferred with the aid
of a 'Zoom Transfer Scope' to a topographic map 1:10'000.
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