Synergism of CIR aerial photographs and SPOT images for monitoring of project housing in Bandung, Indonesia
Comparison between SPOT XS and SPOT PAN reveals that the higher resolution of the black & white (or- in our case-the PAN-XS) image leads indeed to the detection of smaller structures and objects for this type of area. Direction as well as spacing of minor streets can be seen on the image.
Table 1: Development of project housing in Greater Bandung 1981-1987 in 2 sectors (Areas in ha.)
| |
Existing in 1981 |
Built between
1981-July 86
(5 year) |
Built between
July 86-Aug 87
(1 year) |
Total |
North Banding
above 700m |
202 |
68 |
1 |
271 |
| relative |
75 % |
25 % |
0 % |
100 % |
| South Banding |
180 |
368 |
118 |
666 |
| relative |
27 % |
55 % |
18 % |
100 % |
| Total |
382 |
436 |
119 |
937 |
| relative |
41 % |
46 % |
13 % |
100 % |
Information such as in the table 1 gives the planner an insight in and a quantification of the overalls development in Banding's project housing. Although south Banding's is considered as less favorable for housing (mosquitoes abundant in the paddy fields) a considerable shift to that area has taken place because of a lack of suitable land in the northern hills. In 1981 there was more project housing in the hill, north part (above 700 m) than in the south (202) ha against 180 ha). In 1987 the situation was greatly reversed (271 ha against 666 ha). While in the south construction continued in 1987 (118 ha), in the north it came to a standstill (1 ha).
Accuracy of area measurement
Local adjustment of the image to the topographical map makes plotting of the new residential areas possible with an accuracy in the order of .5 or .4 mm i.e. the usual width of a line drawn with a pen. For most planning and management purposes useful enough. For an accuracy test see table 2.
Table 2: New housing areas built between 1981 and 1987 in a test area of Bandung (180 ha),
delineated on SPOT PAN-XS (1:25,000, 1986/1987) and on a small format aerial
photograph (1:10,000, 1987).
Delineated area
built 1981-1986 |
Area on SFAP
ha |
Area on SPOT
PAN-XS
ha |
Difference
% |
| 1. |
6.5 |
6.8 |
6.1 |
| 2. |
11.7 |
13.5 |
11.15 |
| 3. |
2.3 |
2.0 |
-13 |
| 4. |
8.2 |
8.3 |
+1 |
| 5. |
3.7 |
4.3 |
+16 |
| 6. |
0.4 |
0.5 |
+25 |
| 1986-87 |
| 7. |
8.6 |
9.8 |
+13 |
| Total |
41.4 |
44.6 |
+8 |
in table2 we see that for the total area of 41 ha the area delineated on spot is only 8% larger than the area as measured on the detailed small format aerial photograph for the smaller photograph for the smaller p[arts of the area the error lies between planning is fast developing areas this error is fully acceptable. of course the area are grass areas on the small format aerial photographs it is possible to delineate separately the included undeveloped land the difference between such net area and the grass area the test area or less than the growth in one year still fully acceptable for practical use.
The test area is typical for all new housing areas in the southern part of the city where housing projects have been developed in the former paddy fields conclusions for the test areqa may be expanded to all new housing areas in south banding the developing of the project areas between July 1986 and august 1987 could be interpreted from the combined image new project housing areas will have a light tone on the PAN image in the 1986 image these area could have the following colours .
So detection of light red or light blue gray areas usually not far from existing project housing indicated the newly built houses
No confusion with industrial areas
Several large industrial complexes are visible on the SPOT images as well as smaller individual industries they are characterized by their light tone almost white due to the high reflection of the light through the big roofs an industrial building is usually so large that more than one pure roof pixel can be found confusion with new project housing did not occur due to the difference in pattern could be studied first on the false color photographs 1:30,000 from 1981
Other forms of urban growth a subject for research.
Not only project housing and industry an be studied with spot images to monitor the urban growth also other urban land uses can be mapped and measured although with various degrees of accuracy and certainty the growth of industrial areas kampung areas real estate utilities are all examples orf land uses that garbage dumps are can be monitored .for most land uses we do not yet know what the signature on the spot images is we do not yet know whether theswe things can all be seen some further research in this field is the purpose of our current project in binding .
If we compare the spot images the other remote sensing product the aerial photograph the later is b y far superior through its much higher resolution wherever aerial photographs are available they should be used as much as possible how ever research both aerial photographs and the maps derived from them become outdated very soon in a dynamic city like Bandung.
New missions for aerial photography are expensive an can probably be ordered every five with years only in the years in between monitoring could be on done on spot images so that the strategic planning can be reviewed every year. Interpretation of new housing areas on Spot Pan XS the original is a false color image made by combing as 1986 XS with a 1987 PAN image enlarged to1:25,000 this illustration shows a detail in blackn and white enlarged to 1,12,500 the illustration shows a detail in black and white enlarged to 1:12,500.
Areas marked 1 are housing areas existing in 1986
Areas marked 2 and 3 were rural in 1986 but urban in 10987.
Areas marked 2 are light red : red from the paddy in 1986 and light from new urban in 1987.
Area marked 3 are light blue : blue from flooded paddy fields in 1986 and again light from new urban in 1987.
The brightness of the light red and blue depends on the new urban objects usually land prepared for developments a street pattern on the textured of new housing caused by the mix of house garden and street in mixed pixelsthe light red or blue areas are islands in a darker sea and are therefore easily detected. The areas marked 4 and 5 still rurall in 1987n they are dark red indicating growing paddy or dark blue because of flooded paddy land.
Conclusions
- Interpretation of housing areas on spot XS or
PAN XS is greatly enhanced if small scale CIR aerial photography of some
years earlier is available the higher resolution of the photographs
makes identification much more sure even in areas mixed use the housing
areas thus identified on spot as training areas for learning the typical
color and texture.
- Mapping of the new housing areas of the city of
Bandung with a population of 1.5 million could with this method by
accomplished by one experienced interpreter in two working days.
- The delineations of the new housing areas in
SPOT PAN -XS ro be accurate enough for metropolitan planning purposes
when compared with delineations on color small format aerial differed
not more than 15% aerial photography with a scale of the gross housing
areas differed not more than 15% for areas larger than 4 ha fore the
test area is compared difference found was 8% if the gross housing area
from spot is compared with the nett housing area from the airports then
the error for the test area as a whole in 14%.
- Incongruence between the area of jurisdiction
of a municipality and its actual urban area is found in many cities spot
can be very useful for identification of housing areas outside the area
outside the area of jurisdiction of a planning authority reliable maps
derived from spot may influence positively decisions formore realistic
jurisdiction boundaries.
References
- V.F.L. polle monitoring and measuring human
settlement changes by remote sensing methodsa case study with spot
images of bandung Indonesia itc urban survey and human settelment
analysis report fromther bcrs beleids commsssie remote sensing /policy
commission on remote sensing from the nether lands government BCRS
88-16c project no 4533 t03 .11 December 1988 copies of this report be
made available.
- V.F.L polle detection of city growth areas
using spot image interpretation survey pepper for the 16th congress of
the internatoional society for photogrammetry and remote sensing kyoto
Japan 1988 in international archives of photography and remote sensing
volume 27 PART B9 PP VII 3564.
- V.F.L. polle spot image interpretation for information on human settelment growth in proceedings of the asian conference on remote sensing 114 Oct 22-27 198 jakarta indonesia.
