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overlaid aerial imagery. This is due to a system of triangulation based on the<br />
position of the cameras when the photograph was taken. As much of the data used<br />
to extract the sections of aerial photography being analyzed in this study was<br />
captured using this process it is possible that the study could be completed during<br />
this point in data capture. I am referring here to map production, and the stage at<br />
which line and point data are taken from remote imagery. At this stage in map<br />
production it is possible that an-add on process linked to the photogrammetric<br />
software would allow the user to run an analysis of the polygon at the moment it is<br />
fully captured and coded, which in turn would mean that the area marker and<br />
associated polylines could then be given added data of value to the end user<br />
(spectral content of the polygon/ percentage land cover/ rough pasture/<br />
impermeable surface area etc.). I decided against investigating this further for two<br />
reasons. Firstly it would have involved a difficult and time consuming<br />
collaboration with the software provider. Secondly, and more importantly, this<br />
country has been fully digitally mapped and photogrammetric work is now<br />
confined to update only. This means that the application of any algorithm at the<br />
photogrammetric/ data capture stage would be confined to small, mostly urban<br />
areas.<br />
It is difficult to discuss the manipulation of spatial data without reference to the<br />
ArcGIS package of software created by ESRI. This is widely used in both<br />
commercial and educational entities for interpreting spatial data. In terms of this<br />
study the Arc<strong>View</strong> package within ArcGIS could have been utilized for image<br />
processing once the input files were converted to shapefile format. The limitations<br />
imposed by having to obtain a licence for the software (outside of trial/<br />
educational versions) precluded the use of this package. This is not to indicate that<br />
the software would not have been a useful tool for manipulating the imagery in the<br />
study, only that it was not practical at the time of the study..The value of this study<br />
is in allowing new data to be obtained and added to that originally obtained from<br />
an analysis of aerial imagery. While the study identifies one means of doing this,<br />
in terms of software and operating platform ( i.e. executing the process using parts<br />
of the GDAL library and ASCI input files), there are potentially numerous other<br />
software processes that could apply. The algorithm, however, is intended to<br />
remain as independent of software considerations as possible; being constrained<br />
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