www.pcigeomatics.com | © 2010 - Gematica in Action!

Geomatica® in Action!

Scope: As a capstone project for the Advanced Diploma in Remote Sensing and GIS, several students from the Centre of Geographic Sciences (NSCC) participated in a five week field course. The main objective was to collect aerial photography of the Brier Island region of Nova Scotia and produce a mosaicked image. Through their involvement, students gained experience in planning, training, field work, imagery processing, report writing, and presenting.

The study area for the project was Brier Island and Freeport, located on the Southern part of Long Island. Brier Island and Long Island are located in Digby County, Nova Scotia, on the very tip of Digby Neck in the Bay of Fundy. Freeport is approximately 65 kilometres Southwest of Digby, with a short 0.5 km ferry ride across Grand Passage to Westport, Brier Island.

Challenges: There were multiple external parties interested in the final product, including the Nature Conservancy of Canada, the Town of Freeport, and several

residents of the area. Ultimately, the imagery will be used for a wide range of applications including tourism, planning, and search and rescue operations.

Given the large size of the study area and the use of a small-format camera system, it was crucial to automate as much of the processing as possible.

The camera system was comprised of two Canon Rebel XTi cameras mounted back-to-back in a custom built aluminum frame. One camera

collected true color images (RGB) and the other—because of a special filter—captured near infrared images (NIR).

Combining the photographs of these two cameras into a single 4-band image required the combination of an Aerial Photography model and automatic GCP collection. Both were used to align the NIR frame with the RGB frame on an image-per-image basis.

Results: The final data product for this project was a colour balanced mosaic of the Brier Island and Freeport region at approximately 0.5m resolution.

PCI Geomatics Software: The EASI environment was used to perform much of the pre-processing and RGB/NIR image integration. A variety of EASI commands (i.e., FIMPORT, FEXPORT, SETPRO, IIA, ROT & PCIMOD) were used to perform these tasks.

PCI Geomatics’ OrthoEngine was used to create an Aerial Photograph model to align the NIR and RGB frames. This alignment was then imported to the AUTOGCP tool within EASI to collect localized control points for each image. Each NIR frame was then integrated with its corresponding RGB frame using the REG tool.

While PCI was not used to orthorectify the individual frames, once produced, PCI OrthoEngine was used to create the final mosaic.

We used both the Automatic Mosaic and the Manual Mosaicking tools. Additionally, the Hot Spot and Polynomial reduction options removed sun glint and improved the overall colour balancing quality.

Remote Sensing Field Camp 2010Trevor Milne - Professor - Centre of Geographic Sciences

Nova Scotia Community College, Canada

▲ Ortho Unbalanced▲ Frame RGB▲ Frame NIR ▲ Ortho Mosaic

▲ Frame Composite

▲ Camera