| Western Cape Breton Island, Nova Scotia |
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Natural Resources Canada > Earth Sciences Sector > Priorities > Canada Centre for Remote Sensing
Tour Canada from space Western Cape Breton Island, Nova Scotia
 A small portion of the western side of Cape Breton Island, Nova Scotia is shown in this Landsat TM image. The band combination of TM 4, 5 and 3 makes an attractive colour combination where the dominant coniferous forest appears in dark yellow-brown colours. The most recent forest clear cuts are identified by their bright light blue or cyan colour. Other interesting vegetation features include: the purplish areas in the upper left side of the image which appear to be a combination of mixedwood and treed bogs, and an area of predominantly bog and treed bog in the lower right corner.Along the coast, a number of features are identifiable, Margaree Harbour and the famous Cabot Trail. A large valley can be seen running north-south in the centre of the image. This valley contains the North East Margaree River and a number of small communities.
Question: The narrowest logging roads are less than 10m wide, significantly less than the 30m spatial resolution of the Landsat TM sensor. Why can we "see" these roads? [ Answer ]
About this Image
| Location: |
Western Cape Breton Island, Nova Scotia |
| NTS map(s): |
11 /K6, 11 /K7, 11 /K11 (1:50,000) |
 Location Map: |
See a detailed map (1:1M) of the region |
| Image Date: |
September 14, 1990 |
| Satellites/Sensors: |
Landsat Thematic Mapper (TM) Bands 4, 5, 3 (R, G, B) |
| Resolution: |
30 m pixels |
| Image Area: |
27km by 15km |
| Image Features: |
Forest activities, spruce budworm damage, Cabot Trail, beaches, valley, marsh, bogs |
| Related Tour Images: |
Whitcourt, Alberta; Port Renfrew, British Columbia |
| Related Glossary Terms: |
These terms from the CCRS Glossary may help you to understand this image and its interpretation:
false colour, false colour composite, plant reflectance, red edge, vegetation index, leaf area index, normalized difference vegetation index, image texture, tone, brightness |
| Related Tutorial Sections: |
These sections of the "Fundamentals of Remote Sensing" tutorial by CCRS will help you to better understand this image and its interpretation:
2.3 2.5 2.12 5.3
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| Image Credits: |
Received by the Canada Centre for Remote Sensing
Processed by and provided courtesy of RADARSAT International Inc |
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Additional
Information: | Cape Breton Island is enclosed by the Gulf of St. Lawrence on the west and the Atlantic Ocean to the east. Much of Cape Breton Island was infested with the spruce budworm in the late 1970s. This pest defoliated a significant amount of the forest resulting in the loss of 79% of the balsam fir, the predominant species of the natural forest. In an attempt to minimize the loss of wood products, most of the infested areas were clear cut to salvage the useful timber before it had a chance to rot. Now, 20 years later, almost all of the affected forest is regenerating, though there has been a significant decrease in the dominance of coniferous over deciduous trees. The Cabot Trail is a very scenic and well known road in the province. It was named for the famous explorer, Sir John Cabot, who landed on Cape Breton's northern shores in 1497. The trail totals approximately 300 kilometres and winds through highlands, lowlands and ocean vistas. The section shown on the image, travels through the Margaree Valley to Margaree Harbour and on to Cheticamp, just north of the imaged area. |
| Question: |
The narrowest logging roads are less than 10m wide, significantly less than the 30m spatial resolution of the Landsat TM sensor. Why can we "see" these roads? |
| Answer: |
The key to "visibility" is size and contrast. Though the narrow logging roads are definitely "sub-pixel" in resolution, their contrast with the surrounding terrain is very high. Thus they have a noticeable impact on the brightness of the pixel they reside in. (See an explanation of this sub-pixel phenomenon.) |
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