TOPOGRAPHIC MAPPING METHOD USING SPOT IMAGERY
Minoru Akiyama
Map Information Manager
Geographical Survey Insti tute, Japan
ISPRS Comm. |V
ABSTRACT:
Since the SPOT-1 satellite was launched in 1986 SPOT images have been used for medium
scale topographic mapping in various countries both in experimental level and production
level. However, traditional photogrammetric techniques are not always applicable for
SPOT image mapping. because there exist big differences between aerial photographs and
SPOT images. In order to establish practical techniques for topographic mapping using
SPOT images it is essential to standardize specification and procedure. In this regard.
the Ministry of Construction of Japan and the Instituto Geografico Nacional of Peru have
conducted a joint research from 1987 to 1990 aiming to develop and establish practical
methods mainly applicable for medium scale mapping in developing countries.
As results of the four year stüdy. draft of "Standard Procedure and Specification of
Topographic Mapping using SPOT imagery" and "Manual for SPOT Image Interpretation” were
obtained. Those documentations are expected to be used for overseas mapping and
technology transfer programs in International Cooperation Aids of Japan.
KEY WORDS: SPOT. Mapping, Specification, Standard Procedure, Interpretation Manual.
1. INTRODUCTION From this point of view. the Ministry of
Construction and the Instituto Geogtafi co
SPOT HRV sensor was designed to be able to Nacional of Peru have conducted a joint
obtain ‘stereo pair images of the earih's research from 1987 to 1990. The
surface and expected to be used for objectives of the research are those as
photogrammetric mapping. In order to follows.
roalizo stereo plotting of SPOT data,
several softwares running on analytical (1) Development of method to get the best
plotters have been developed and quality images for interpretation.
introduced on market so far. Moreover, (2) Accuracy analysis of "SPOT image
many topographic maps have been produced plotting.
using SPOT images in many countries both (3) Development of practical method to
as in experimental work and in practical extract image control points.
work. Thus. mapping method using SPOT (4) "Analysis for plotting limits of SPOT
data is seemed to be established to some imagery.
extent. However, topographic mapping is (5) Development of Practical method for
very comprehensive technology which is field completion survey.
composed not only of stereo plotting .but (6) "Collecting examples of "SPOT image
also of photo interpretation, field interpretation.
completion, compilation and reproduction.
Therefore, the development of stereo As results of The four year‘ study, the
plotting software is only a necessary following two documents were formed.
condition but not a sufficient condition
for the development of total method of (1) Standard Procedure and Specification
mapping. of Topographic Mapping using SPOT
imagery.
SPOT images are very different from aerial (2) Manual for SPOT Image Interpretation.
photographs not only in their geometrical
property but also in their radiometric
property. Observed wave bands are sifted 2. IMAGE ENHANCEMENT TECHNIQUE
to longer side including near infrared
band and excluding blue band. The 2-1 Study flow
resolving power of SPOT images is
officially stated as 10m for panchromatic Gray levels of SPOT data are concentrated
mode and 20m for multi-spectral mode, to lower level and contains detector
which is getting worse according to noises. This make an image very flat and
weather and atmospheric condi tion. Those make interpretation difficult. Therefore,
characteristics may affect image in prior of plotting, it is important to
interpretation very strongly that there improve image quality by stretching image
might need additional field completion contrast and removing detector noises.
work and might reduce economical advantage
of SPOT image mapping. Therefore, it is In order to determine appropriate pre-
indispensable for establishing practical processing to produce good quality film
method of topographic mapping using SPOT outputs out of SPOT data. several density
data, that we have to clarify plotting transformation functions were examined and
limi tati ons of SPOT data and to make up evaluated.
new specifications of maps.
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