of user disk space, a 19-inch monitor with 
Stereographics, Inc., "CrystalEyes" infrared 
emitter and glasses. 
Also delivered as part of the system were a 
Tecktronix Phaser IIsd printer and a Versatec 
electrostatic plotter. 
The server and workstations are connected through a 
dual-ring FDDI fiber optic network. Additionally, the 
server, workstations, and plotter are each individually 
linked to the main Ethernet network. In addition to 
allowing each NARSAP workstation to communicate 
with and transfer data to other production systems, 
this linkage provides backup to the FDDI should it fail 
for any reason. Although considerably slower in 
moving large image files than the FDDI, the NARSAP 
system at least will not be brought to a halt. 
When the functional specifications were being written, 
one goal was that there be a single common user 
interface for all functionality, photogrammetric, image 
processing, and GIS. This goal was not fully achieved. 
The ARC/INFO functions were not fully integrated 
into a common user interface, but the link between 
ERDAS Imagine and ARC/INFO was made 
transparent by using the ARC/INFO data structure to 
store vector and attribution data. The vector module 
of Imagine will allow selective display and editing, 
including attribution, of vector data. The data are 
stored in an ARC/INFO file structure. An operator 
who needs to perform analysis functions on the vector 
data, such as polygon overlay, buffer zones, and so on 
must operate in the ARC/INFO HMI structure. The 
derived vector data sets can then be displayed in 
ERDAS over images. 
The only requirement in the specification not fulfilled 
by the off-the-shelf system purchased was the 
capability to display vector information superimposed 
over a three-dimensional model. Because the GIS that 
was chosen does not store elevation information with 
each digitized point the digital elevation model is used 
to assign an elevation to GIS features. Features above 
ground level will not be displayed at their true 
elevation. 
As the accompanying concept-of-operations diagram 
indicates, no simple data flow through the system takes 
source data and produces a product. An almost 
unlimited variety of ways are available to enter and 
move data through the NARSAP system, which was 
one of the goals of the design: to make as versatile a 
system as possible within the limitations of 
photogrammetric, image processing, and GIS 
technologies at a reasonable cost. Therefore, the 
concept of operation for NARSAP depends entirely on 
what one wants to accomplish. The output of virtually 
all system capabilities can be products in themselves or 
become intermediate steps providing data for further 
integration and analysis. 
NARSAP APPLICATIONS 
It is hoped that bringing together scientists and 
researchers from various disciplines will lead to the 
development of specifications for new remote sensors 
and image exploitation systems and to the better use 
of existing systems in providing improved capabilities 
for environmental assessment, for emergency response 
planning, and for resource monitoring and assessment. 
  
  
  
  
  
  
m d 
Imagery «c- Ima 
2 
3D Module 
     
  
  
*— DEM 
1» D0Q 
  
  
  
Figure 2 Operations Concept 
  
276 
Areas of 
phase 1 
assessm 
environ 
crop, fo 
assessm 
mineral: 
wetland. 
Federal 
sensing 
Studies