Page 164 - Digital Analysis of Remotely Sensed Imagery

130 Cha pte r F o u r

Geomatica 10 functions perfectly well for images saved in the
PCI proprietary format that is useful in bringing together multi-
source information about a study area, facilitating data manipu-
lation, analysis, and organization. Images in the JPEG format are
acceptable to Geomatica, but should be converted into the pro-
prietary format for all data manipulations to achieve higher
efficiency.
PCI is able to display images in a range of manners. Both raster
and vector data can be displayed and integrated, though good
response times are essential in displaying high resolution imagery of
a very large size. Three-dimensional viewing and vector feature attri-
butes may be built, edited, and queried in the 3D stereo environment.
In addition to images, raster DEM data may be displayed with eleva-
tion color coded. Interactive fly-throughs may be created from imag-
ery data in FLY! for topographic visualization. With the assistance of
this visualization tool, imagery and vector layers may be draped over
a DEM to create perspective scenes in near real-time. The user is able
to interactively control flight speed, viewing direction, elevation, and
perspective parameters through the intuitive point-and-click user
interface.

4.5.2 Major Modules
PCI encompasses many image analysis modules for various process-
ing tasks, such as geometric correction, image classification, data
visualization, and cartographic production. The two most important
modules in Geomatica are Focus and OrthoEngine. The former offers
a comprehensive range of tools for undertaking an image analysis
task from beginning to end. The input data may be transformed to an
extensive range of projections, which can be user defined. The trans-
formed image can be subset or clipped through advanced spatial
operations. The map and file trees of Focus keep the image analyst
abreast of the workflow as the image is being edited and modeled.
OrthoEngine is a complete photogrammetric suite of image geo-
metric processing tools, such as geometric rectification, orthorectifi-
cation, image mosaicking, DEM extraction, and 3D visualization.
This powerful tool is designed to produce geometrically corrected
images and mosaics efficiently. It allows mosaicking of even nongeo-
referenced oblique images using the polynomial model. It is possible
to sequentially step through matching points within the geocoded
images. However, it is through manual manipulation that the analyst
has more control over final output quality.
In an enterprise setting, not all available functions in a compre-
hensive software package are used equally frequently. Instead, the
image analyst may perform certain tasks repeatedly. High efficiency
is achievable if such specific functions are initiated and accessed
conveniently. PCI tailors this access through a particularly useful