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the new housing occupancy, and the desire to secure
mortgages by registration, all within the framework of
a Torrens type cadastral system.
The recognition of the need to establish a National
Digital Mapping Database, brought with it the need for
re-mapping.
2.1 Re-Mapping
In 1992, following the decision to entrust the Survey of
Israel with the responsibility for coordination of the
various government sponsored or funded GIS
activities, the basic layers and standards for the
National Digital Mapping Database (NDMDB) were
defined.
The foundation layers of the “National G.I.S.” were to
serve, both map series production by the Survey and
the national data source for spatial information
analyses.
The basic concept is to establish a seamless, unique
and homogenous database.
The re-mapping project is based on photogrammetric
mapping from 1:40 000 scale aerial photographs.
Private photogrammetric companies were
commissioned, under bid, to carry out the data
acquisition. Quality control is in the hands of the
Survey of Israel.
Data which have passed the quality control are
integrated into the NDMDB, by joining the models,
building attributes tables, marking each feature by its
source code and refiling the merged data into the
Survey's database files.
Look-Up-Tables (LUT) permit derivation of 1:5000,
1:10000, 1:20000 and 1:25000 map scales. The data
collection has reached approximately 30% per cent of
the country’s area, mainly in the developed areas.
22 Photogrammetry for cadastre
Mutations to the existing land settlement subdivisions
require the preparation of a registration plan, which
complies with the approved planning documents and
with the Survey Ordinances. A project was undertaken
by one of the private companies to produce a
registration plan with an orthophoto background.
Aerial photography at the sale of 1:5000 was
controlled by presignalised GPS points. The
photographs were scanned at 12p density and the
solution supplied conformed with the standard of 4cm,
both in position and elevation. The photogrammetric
map at 1:1250 scale required some field completion.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996
Following mapping, a DEM was derived with a 5 m.
density in hilly areas and 8 m. in flat areas. On this
DEM basis an orthophoto was produced with a ground
resolution of 8 cm and this served as a basis for the
subdivision. The subsequent field check proved that
95% of the subdivision points complied with the
accuracy standard without any additional field surveys.
It appears, however, that from the cost/benefit point of
view, the digital photogrammetry/orthophoto method
is more expensive than the conventional combination
of photogrammetric and field surveys.
The conventional procedure is based on
photogrammetric survey of detail and field survey of
boundaries, both connected to uniform GPS control
network. :
At the present, some 470 projects are in various stages
of execution, involving some 120,000 housing units,
the registration of public housing receiving very high
priority.
2.3 Aerial photography and related products
There are six modern major aerial cameras in Israel,
the Survey owns an RC 30 and an RC 8, and Ofek,
Aerial Photography Ltd., the largest private aerial
photography company, owns an RMK TOP and several
other cameras. Ofek owns two planes for aerial
photography, an additional plane for oblique
photographs and a helicopter for electronic and video
cameras.
The Survey has a black and white photo lab., whilst
Ofek Ltd. handles colour, black and white and infra
red photography.
Contact prints and enlargements are very popular
products with the Israeli customers and the total sales
of these products in 1995 are estimated at
approximately $1,400,000.
Aerial photographs are admissible as evidence in
courts of law, if supported by an appropriate
declaration of a photointerpreter and some 40 cases per
year are dealt with by courts on this basis, pertaining
to rights to land.
2.4 Photogrammetry for engineering and
special surveys
Urban and rural planners, public works engineers and
architects, require topographic map background,
usually in digital output form. It is estimated that some
400 projects in this field were executed by private
photogrammetric companies.
In the year 1993 a special project was carried out for