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Natural Resources Canada > Earth Sciences Sector > Priorities > Canada Centre for Remote Sensing
Tour Canada from space Nepean, Ontario
 Nepean is one of the suburban cities that surround Ottawa, Ontario, the capital city of Canada. This autumn image was acquired using the MEIS sensor, on board the CCRS Falcon Fanjet aircraft, which provides very high resolution data. Where suburbia meets the rural lands, a variety of natural and artificial "targets" may be seen. A stream winds its way through agricultural fields, under a road, beneath several power lines and beside a residential subdivision. In this neighbourhood, natural stands of trees are accompanied by a planted stand. The very high resolution and sensitive MEIS scanner has depicted features such as subtle shadows, sewer/manhole covers, colourful fall foliage, swimming pools and hedges. While feature shape, texture, pattern, colour and position all help in interpreting the image, it is context, or knowledge of ambient conditions that allows in-depth analyses by visual means.
Question: Why are the fields on the left side of the image uneven in colour? [ Answer ]
About this Image
| Location: |
Nepean, Ontario |
| NTS map(s): |
31 G/5 (1:50,000) |
 Location Map: |
See a detailed map (1:1M) of the region |
| Image Date: |
October, 1993 |
| Satellites/Sensors: |
MEIS, airborne (bands 448nm, 553nm, 641nm displayed as R,G,B) |
| Resolution: |
0.5 m pixels |
| Image Area: |
Approximately 0.5km by 0.55km |
| Image Features: |
Intersections, fields, power lines, planted trees, houses, cars, fences, swimming pools, hedges |
| Related Tour Images: |
Residential Suburb - Kanata, Ontario |
| Related Glossary Terms: |
These terms from the CCRS Glossary may help you to understand this image and its interpretation:
MEIS, image texture, tone, brightness, contrast, spectrometer |
| 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 4.2 5.5 5.7
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| Image Credits: |
Acquired and processed by the Canada Centre for Remote Sensing |
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Additional
Information: | Data from the MEIS airborne sensor is very high quality and high resolution. Information can be collected from the visible and near infrared portions of the electromagnetic spectrum. In the case of this image, the 3 bands (448nm, 553nm, 641nm) were collected in the blue, green and red portions of the visible spectrum. When they are displayed together in this fashion, you see an image that looks a lot like a regular colour photograph. MEIS imagery has been used for a number of applications including: insect damage assessment in forests, clear cut mapping, terrain profiling, vegetation stress monitoring, and marine oil spill measurement. In contrast to an airphoto, which the MEIS imagery mimics, the digital MEIS data can be calibrated to allow precision, repeatable and comparable measurements of colour and brightness. The extraction of meaning from the colour and brightness is the job of the remote sensing specialist. |
| Question: |
Why are the fields on the left side of the image uneven in colour? |
| Answer: |
Usually a farmer wants to grow the same vegetation throughout a field; certainly different crops would not be scattered apparently randomly throughout the field, which would make harvesting very difficult. So we may deduce that the colour "patchiness" of the green field is not a variation in plant types. In fact, we can be certain that the colour variation is not intentional, so it is likely naturally caused. In this field, the brownish areas are thinner patches of the growing plants, while the slight changes in the colour can also indicate moisture or other forms of stress. Images such as this can aid the farmer in minimizing the cost and effort of applying fertilizer, herbicide, water, etc. to a field, by showing which parts of the field need more of the application than others. This technique is being developed in a technology called "precision farming". |
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