433
Development of a Spatial Decision Support System
system searches through the available data to identify those regions that meet the user
requirements. Fig. 5 shows a screen dump of the Boolean search panel and the resultant
map.
One of the more complex models included in the system describes the accretion of
sediments on a saltmarsh (Wadsworth and Pakeman, 1996). This hybrid model consists of
AML code and an external C programme and makes use of remotely sensed data from the
Compact Airborne Spectral Instrument (CASI), a digital terrain model (DTM), published
parameters for predicting tide levels and field data on sediment trapping in vegetation.
CASI data have been classified into 18 types, ranging from well established mature
saltmarsh, through developing and pioneering saltmarsh to algae-covered muds, bare
sediments and water (Thomson et al., 1994).
The saltmarsh model outputs an accretion rate that can be used to estimate new
beach profiles and generate a new DTM. As plant species exhibit different abilities to
tolerate inundation and exposure, a new beach form can be used to predict the movement of
different vegetation zones. The revised location of the zones will in turn affect the accretion
and erosion rate. In this way the interdependent interactions between biota and the physical
environment can be simulated. Preliminary results from the North Norfolk site indicate
average deposition rates three to four times lower than the mean prediction for sea level rise
over the next century. A more detailed description of this type analysis is found in
Wadsworth and Pakeman (1997). An example is shown in Fig. 6.
Discussion
The LOIS Decision Support System has adopted a significantly different approach to data
access that has proved effective during the lifetime of the project. The policy of retaining
data in its native form has not presented us with insurmountable problems or lead to
significant decrease in efficiency in data processing, analysis or display.
Distributed hybrid data bases are feasible across the local area network (LAN).
Such data bases allow a single image of the data to be maintained and curated, simplifying
data audits and quality control, while the increase in access time is still manageable. Access
across the LAN shows the potential for practical applications across the Internet and the
dissemination of data and models both within the research community and to a wider
audience.
The complexity of commercial GIS can be adequately managed by the
development of simple graphical user interface (GUI). An adequate GUI can be constructed
quickly using facilities within ArcInfo. Any loss in robustness, flexibility and speed are not,
for this application, significant deterrents.
Development of a Spatial Decision Support System
system searches through the available data to identify those regions that meet the user
requirements. Fig. 5 shows a screen dump of the Boolean search panel and the resultant
map.
One of the more complex models included in the system describes the accretion of
sediments on a saltmarsh (Wadsworth and Pakeman, 1996). This hybrid model consists of
AML code and an external C programme and makes use of remotely sensed data from the
Compact Airborne Spectral Instrument (CASI), a digital terrain model (DTM), published
parameters for predicting tide levels and field data on sediment trapping in vegetation.
CASI data have been classified into 18 types, ranging from well established mature
saltmarsh, through developing and pioneering saltmarsh to algae-covered muds, bare
sediments and water (Thomson et al., 1994).
The saltmarsh model outputs an accretion rate that can be used to estimate new
beach profiles and generate a new DTM. As plant species exhibit different abilities to
tolerate inundation and exposure, a new beach form can be used to predict the movement of
different vegetation zones. The revised location of the zones will in turn affect the accretion
and erosion rate. In this way the interdependent interactions between biota and the physical
environment can be simulated. Preliminary results from the North Norfolk site indicate
average deposition rates three to four times lower than the mean prediction for sea level rise
over the next century. A more detailed description of this type analysis is found in
Wadsworth and Pakeman (1997). An example is shown in Fig. 6.
Discussion
The LOIS Decision Support System has adopted a significantly different approach to data
access that has proved effective during the lifetime of the project. The policy of retaining
data in its native form has not presented us with insurmountable problems or lead to
significant decrease in efficiency in data processing, analysis or display.
Distributed hybrid data bases are feasible across the local area network (LAN).
Such data bases allow a single image of the data to be maintained and curated, simplifying
data audits and quality control, while the increase in access time is still manageable. Access
across the LAN shows the potential for practical applications across the Internet and the
dissemination of data and models both within the research community and to a wider
audience.
The complexity of commercial GIS can be adequately managed by the
development of simple graphical user interface (GUI). An adequate GUI can be constructed
quickly using facilities within ArcInfo. Any loss in robustness, flexibility and speed are not,
for this application, significant deterrents.