International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
  
  
(c) 50cm mm 
Figure 5: 3D Photo-textured Reconstruction of an Intertidal Rockflat: (a) 3D oblique view of the rock platform, (b) medium-level zoom 
oblique view of rock platform section, (c) full-zoom overhead view of individual rockpool. The level-of-detail visualisation system 
allows for different model scales to be visualised in a single, continuous terrain model. 
Boulder Field ES 
Rack Pools n T Lure Cliff Edge 
X ^ 
        
Sa: 
Figure 6: 3D Photo-textured Reconstruction of an Intertidal 
Rockflat: Perspective view from the southern end of the 3D ter- 
rain reconstruction with annotations illustrating landscape fea- 
tures/habitat types at the site. 
ing pipeline took approximately 4.5 hours running on a process- 
ing server with two six-core, 3.3GHz processors with most time 
spent performing image processing tasks such as feature extrac- 
tion and matching. The same processing pipeline was performed 
on a dual-core, 2.4GHz laptop for comparison, taking approxi- 
mately 17 hours to complete. 
3.2 Mapping Results 
Figure 4 illustrates the final photo-mosaic of the intertidal rock 
platform and existing manned aerial photography of the the Cape 
Banks area for reference. Along the western limit of the map is 
the waterline to the bay and along the eastern limit in the map is 
a steep cliff-face which is permanently above the high tide water- 
line. 
Figure 5 shows the 3D photo-textured model of the terrain recon- 
struction. The final 3D terrain map displayed a 3D topographic 
resolution of approximately 0.25 points/square-cm and a photo- 
texture resolution of approximately 2-4mmy/pixel. Figure 5 (b) 
and (c) illustrate zoomed-in views of the 3D model from medium 
scale to fine-scale views. The level-of-detail visualisation system 
allowed for different model scales to be visualised in a single, 
continuous terrain model. The highest level of detail information 
provides detailed structural information on individual rock pools 
with colour information indicating the presence of micro-algae 
coverage and assemblages of gastropods such as periwinkles and 
limpets. 
The site exhibits a number of habitats visible in the mosaic such 
as rock pools, boulder fields and crevices between the rock (see 
Figure 6). 
3.3 Potential Applications in Intertidal Ecology 
The presented mapping technique provides two primary types of 
information of interest for the study of intertidal ecosystems with 
a high level-of-detail over large areas that would be infeasible us- 
ing traditional sampling methods. Topographic mapping allows 
for high-resolution measurements such as rugosity, vertical posi- 
tion on the shore with respect to tides and the slope and aspect 
with respect to the sun over a large area. Photographic mapping 
allows for the identification of intertidal species present during 
imaging and has the potential to provide data on variables such 
as chlorophyll/ algal biomass with the addition of near-infrared 
images. 
To reliably detect human and environmental impacts on plant and 
animal populations it is necessary to sample populations at sev- 
eral times and at appropriate spatial resolutions before and after 
the impact (see (Underwood, 1994)). Often, it is not possible to 
do this either for logistical or cost constraints, thus reducing the 
reliability of the detection of change. Our low-cost method al- 
lows for collections of data across a cascade of spatial scales and 
potentially at extremely fine temporal resolution, allowing for ap- 
propriate sampling to be made. This would be especially valuable 
for example in distinguishing natural changes such as seasonality 
    
   
  
   
  
   
    
   
  
  
  
  
  
  
  
  
  
  
  
  
  
  
   
   
   
   
     
    
    
   
   
    
   
   
    
   
    
     
    
  
    
   
   
   
   
   
   
   
     
   
   
   
   
    
   
        
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