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Datasets / St. Lawrence Global Observatory

Aerial Photo Mosaics of the Coasts of Quebec (2015-2024)

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The project of aerial photography acquisition and mosaics construction aims a better understanding of the eelgrass beds extends on the Quebec coasts. These mosaics will allow us to segment the images in order to create polygons of the extent of the eelgrass and thus monitor its growth over time.
The photos captured vertically following the flight lines previously provided by the DFO were georeferenced and orthorectified with a ground resolution of 30 cm. The digital multispectral camera was placed on an aircraft at a constant altitude for the duration of the flight, to obtain a swath of at least 4 km on the ground. An overlap of 60% to 80% was requested in order to optimize the image during mosaicking.
Certain environmental criteria had to be respected to ensure images homogeneity. Shooting had to follow low tide as closely as possible, and be synchronized with the period of the day when the sun's elevation angle was greater than 25 degrees. Wind speed had to be less than 20 km/h, waves less than 1 meter high, and there had to be no cloud cover or fog under the aircraft. Water turbidity had to be taken into account to ensure identification of eelgrass beds in the water. These flights were carried out to coincide with the eelgrass growth period.
Subsequently, the mosaics were created in ArcGis, taking care to select the right order of images to minimize specular reflection.

Data and resources

Additional information

Temporal extent2015-07-15 – ongoing
Vertical extent0 – 0 m
Date (creation)2015-07-15
StatusonGoing
Update frequencyasNeeded
Metadata languagefr
Licensegovernment-open-license-canada
Source metadataISO 19115 XML
Last updated2026-07-31
Created2026-07-31
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