It has been my assertion that remote sensing had been, and still is,
driven by the needs of geoinformation users. It differs from GIS, however,
in that national governments have had much greater involvement historically
due to their funding of military applications and, to a much lesser extent,
their concern with environmental issues in recent years. In both cases
government agencies are the principle end-user. The only market sector
dominated by private companies has been geological applications, and in
particular mineral exploration. The emergence of commercial remote sensing
and the availability of sub-metre resolution imagery from satellites (largely
as a spin-off from military activity) are likely to result in a shift
in the balance of applications from the natural to the built environment.
Much of this movement, however, will not be due to the creation of new
applications since I anticipate many users will only be converting from
aerial photographic to satellite image sources of data. New applications,
however, are emerging because of the improved availability and accessibility
of these data e.g. the increased frequency and scheduled reliability data
acquisition, consistent data quality, digital format, ease-of-import to
image processing/GIS software. These are operational issues. Alun Jones
of The Geoinformation Group compiled a list of questions to consider before
buying digital imagery as a data source.
- What information do you require for your application?
- Where you can buy it?
- What format it comes in?
- How long it will take to get the imagery you require?
- How much it costs (and whether it is worth it)?
and a single scientific question:
- Will it meet will all (or some or none) of your information needs?
The point I wish to make is that the latter question is still a key element
to any Earth observation strategy using remote sensing. You need to understand
the principles of the remote sensing system - of electromagnetic radiation,
of energy interactions with targets, of platforms and sensors. You need
to understand how a signal detected by a sensor is calibrated and formatted
into multispectral images and how to extract meaningful Earth surface
information from them. As a student of remote sensing and image analysis
you should be able to design and implement a successful strategy for applied
remote sensing. In this topic we will postulate on future directions for
remote sensing and consider how remote sensing and GIS are likely to develop.