This has an extremely important consequence. So far, in
several countries, notably developing countries, digital image
processing facilities, if at all available, are or were in a central
place, usually in the capital.
Access is difficult for a number of reasons, but one is that
those around these facilities have become a class of
knowledgeables, who guard their exclusive status.
"Knowledge = power" and therefore they are not very eager to
impart their knowledge onto others who might become
competitors. The very high price of large image processing
systems and spare parts was a safeguard to their exclusive
status. It meant that (semi) (government) agencies and private
consultants and other enterprises were dependent on the central
facility.
This is now changing: Image processing facilities of
stand-alone capability based on PC's are now within the
budgetary reach of institutes like the soil survey, the bureau
of agriculture, the geological survey, but also the national
mapping agency, the national planning bureau, and also the
offices of local authorities.
They can become independent of the central facility. Hard-and
software developments are such that many of the functions are
routine and hardware-based operations, more or less
fool-proof, and do not require a special operator. The interpreter
or the user can now do his own processing.
It may be taken for granted that the industry will take care of
market penetration, but that market is not the market of image
processing and GIS. It is the market of the Personal Computer
in general usage, complete with its collection of easy-selling
software (games !, bookkeeping, spreadsheets, textprocessing).
Only through their massive production and marketing these
PC's have become affordable and increasingly powerful.
Adaptation of these systems to digital image processing and
GIS has resulted in an ample choice of systems available for the
user today. ■
8.2 Base map updating
Another interesting aspect is that topographic maps are often
years out of date. If available, they are mostly the base on
which interpretation data and other pertinent information is
plotted. It becomes now possible - with the high resolution
SPOT and IRS 1C and D data- to do rapid map updating, and
the national mapping agency is no longer the only one who can
do that! It can be done right at the resource agency (soils,
geological, forestry services, regional and local planning offices
etc.) It means that resource managing agencies at the local and
regional (district, province) level, can do their own rapid map
updating and produce reliable field maps as well as base maps
for plotting the results of their surveys.
8.3 Data supply
RS data is now available on an operational basis, in the sense
that the supplier guarantees continuity of the data stream for a
given period. That means that for the first time now, it becomes
a sensible proposition for mapping agencies, to use RS data
(SPOT or Landsat) as an data source. So far, there was no
question of it, as we were still in experimental and
proof-of-concept phases. Still, the situation is rather uncertain
as to the real operational continuity in data supply, especially
from the Landsat series.
8.4 Monitoring changes
A new aspect, and a problem, is our inexperience in handling
changes in situations or configurations at the earth's surface.
We are used to the mapping of an existing situation, -which, by
the way, is shown on a map that appears months if not years
after the survey-, but not to the "mapping" (monitoring) of
changes.
Remote sensing, certainly in combination with scanned air
photos and GIS, is capable of monitoring changes by the
repetitivity of observations, and of showing them.
8.5 Commercialisation
Along with operationalisation comes commercialisation:
Data are no longer being paid for by the (US) taxpayer, but by
the user. That has given rise to a substantial increase in prices,
bringing them to a realistic level from the almost-free level of
the early days. Still, per square kilometer RS data is in the
order of US$ 0.50 as against about US$ 2.50 for normal
high-altitude aerial photography.
But the number of sq. km per satellite scene is a constant, and
the user may not need all of them.
Users in Developing Countries usually complain about the cost
of the data. It should be realized however, that the cost of image
processing equipment has decreased dramatially.
It should be noted that aerial photography retains, of course, its
fully operational status as a data source.
8.6 Resistance to institutional change
In any established mapping or resource management, or
planning agency, vested patterns of authority, (in)competence
and job security coupled with bureaucracy are natural factors
resisting change.
Even if satellite data would be a reliable flow of basic data, then
still it takes long and patient pushing before established routines
in an agency are changed.
Pushing too hard will also backfire.
8.7 Security hocus-pocus.
One way of exercising authority is declaring air photos and/or
satellite or radar data of strategic value and imposing security
restrictions on their use. Many potential users fight an uphill or
losing battle against often senseless restrictions, and eventually
give up.
This happens in many countries and is an important reason for
the under-utilization of aerospace remote sensing data in the
widest sense, for purposes of mapmaking, resource evaluation
and environmental management.
The feeling of the present author is that international scientific
associations and agencies in the field of remote sensing
applications, are not enough aware of these factors. They