94 
pointing capability which result in 1) higher 
temporal coverage and 2) stereoscopic image 
recording. The thermal channel of the Thematic Mapper 
has a spatial resolution of 120m*120m in stead of the 
30m*30m of the rest of the channels. In comparing 
the Thematic Mapper and the SPOT characteristics it 
may be expected in general that the Thematic Mapper 
is better equiped for thematic information extraction 
and SPOT is better suited for cartographic 
applications because of its stereoscopic capability 
and the 10m*10m resolution panchromatic recording 
mode. 
Table 1. Sensor characterisctics of Landsat-4 and 5 
Thematic Mapper and Spot system. 
Sensor: 
TM 
SPOT 
Launch 
06/1982 
22/02/86 
resolution(m) 
30*30 
10*10 
20*20 
spectral channels( 
nm) 
(MSS) 
1 
450- 
520 
500-590 
2 
520- 
600 
600-680 
3 
630- 
690 
790-890 
4 
760- 
900 
5 
1550- 
1750 
6 
2080- 
2350 
7 
10.3- 
12.5 (um) 
scene coverage(km) 185*185 60*(60 to 85) 
temporal 16 days period 3-5 times/26 days 
resolution 
3.2 Thematic Mapper geometric accuracy 
Next to the characteristics of the satellite system 
the accuracy of the registration of satellite imagery 
to maps plays an important role. The geodetic 
accuracy or scene-to-map registration accuracy is 
dependent on the accuracy with which the Ground 
Control Points (GCP's) can be indicated on the 
imagery and on the map, the topography of the area 
concerned and the algorithms used for the 
registration. For favorable conditions, the rectified 
TM data can meet NMAS (US cartographic standard) for 
map products at scales to 1:24.000 but typical GCP 
configurations and average terrain conditions will 
conform to standards for 1:50.000 to 1:100.000 scale 
maps (R.Welch, 1985). It is expected that in general 
these accuracies will be higher in the Netherlands 
because of better opportunities for GCP location and 
because the error associated with relief displacement 
can be neglected. Therefore it is expected that a 
1:25.000 scale accuracy can be achieved. 
3.3 Discussion with planners 
In 1984 and 1985 DHV organized a series of meetings 
with central, provincial and local authorities 
occupied with the planning and management of land and 
water. During these meetings an inventory was made of 
the needs of satellite imagery derived information. 
The meetings lead to the following conclusions: 
- the detail on the high resolution satellite imagery 
makes it a valuable source of many relevant informa 
tion 
- this information can add in a cost-effective way to 
many planning and manegement applications 
- the information present in the satellite imagery is 
not accessible to most of the planners, because 
they are not familiar with the interpretation and 
techniques involved in using satellite imagery. 
These conclusions formed the reason for DHV Consulting 
Engineers to develop techniques to present the satellite 
derived information in a more user-friendly way. 
This lead to the development of the Satellite Thematic 
Map concept. 
4 RESULTS 
4.1 Thematic content of the Thematic Mapper imagery 
of the "Kromme Rijn" Area 
The information content of the imagery was evaluated 
by comparing the imagery with the topographic map 
1:25.000 and vegetation/land use maps of the area. It 
was shown that the spatial resolution of the Thematic 
Mapper imagery was sufficient to discriminate between 
idividual fields. This was also confirmed during a 
field check. The color classes which could be discer 
ned on the Thematic Mapper imagery showed a very good 
resemblance to the land use classes of the topographic 
map. 
In general grassland,forest (coniferous, deciduous and 
mixed), agricultural fields, orchards, cities, villa 
ges and surfacewaters could be made from the imagery. 
In addition some refinements to the legend of the topo 
graphic map could be discriminate on the imagery. 
A differentiation between mais and fallow land, old 
and young apple orchards and management practices, 
for example the clearing and cutting of forest areas 
could be established. Also small linear tree-elements 
with up to a sub-pixel dimension could be 
distinquisted. However the possibilities for the 
inventory of very small (linear) features with 
Thematic Mapper imagery seems restricted and must be 
evaluated for every case in detail. 
4.2 Combination of satellite imagery with the 
topographic map 
However to actually derive a land use map from the 
satellite imagery the interpretation of a especially 
forest, mais and orchards was difficult. 
By overlaying the satellite imagery with the 
topographical map this problem could be solved and an 
high accuracy interpretation became possible. 
Figure 1. Satellite Thematic Map of the "Kromme 
Rijn" Area: scale 1:25.000. 
4.3 The 
As a t 
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1984. F< 
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5 C0NCLUS 
From the 
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by using 
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a large i 
forms a f. 
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presentat: 
For instai 
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Thematic f 
a raster c 
very suit 
Land Infoi 
combinatic 
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derived fr 
of SPOT wi 
instance i 
detailed 
Satellite 
for prese 
new gener 
satellites 
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REFERENCES 
Colwell,R.i 
and 2, 
Sheridar 
End report 
research 
of Remot 
Dutch) 
Landsat-4 S 
Vol. 1-4 
Lillesand,T 
image in 
T.R.Jord 
Evaluate 
cartograj 
Thematic Maj 
Engineer: 
Spot simulal 
the 1984 
Corporate