Géolocation was entrusted the realization of the orthophoto for the city of Trois-Rivières. Since its foundation in 1980, the firm realizes projects of aerial imagery and derivatives like orthophotos and orthomosaics. These high-resolution products are more and more in demand by the cities and RCM and even become musts. To date, the CMM, Québec, Shawinigan, Granby, Rimouski, Sainte-Anne-des-Monts and all the coastal villages in Nunavik have benefited from our expertise. This spring it will be Trois-Rivières’ turn to fully live the Géolocation’s experience to count on some of the most skilled team.


Planning and aerial imagery

The period of acquisition for this project was completed this spring 2018, after the snow melt and before the full green-up of the trees, around mid-May. In addition to this weather constraint, there were other specifications that caused the reduction of this already brief acquisition window. The ideal day could be summed up by low humidity in the air and a sky without any clouds. The aerial imagery was also captured outside of the periods with sun at its zenith to avoid the sun spots on the images.

An appropriate flight planning was the key to perform the acquisition with respect to the technical guidelines requested by the city : ground resolution of 8cm, low variation of the flying altitude, overlap of 60% and sidelap of 30%.

In complement to the aerial imagery, the planning of the field surveys was necessary to evenly distribute the control points within the area of interest. They have been properly located to enable their interpretation in stereoscopy during the adjustment process of the images.


Orthophotos and other photogrammetric products

Once the aerial imagery completed, Géolocation now proceeds with the photogrammetric processes to generate the following products :

  • photogrammetric models (stereoscopic couples) to visualize images in 3D with specialized softwares and equipments;
  • digital terrain model, that are an accurate representation of the territory;
  • orthophotos, these photos you can superimpose with a map to measure distances;
  • orthomosaics, the fusion of orthophotos with invisible transitions.


Which cartographic use?

Without limitation, all these products are visual and relevant sources of information to municipalities for:

  • the development of land use plans;
  • the zoning regulations : agricultural, industrial, residential …;
  • the establishment and management of municipal infrastructures such as buildings, roads, pluvial sewer systems and health network;
  • the monitoring of risk areas like flood and landslide areas;
  • the collection of taxes for the exploitation of quarries and sand pits;
  • the update of the background for interactive maps.


If you are interested to get photogrammetric products with very high quality and resolution, Géolocation will support you during all your project to offer you customized products that meet your expectations.