Canada Centre for Remote Sensing
Tour Canada from space
Nepean, Ontario
Larger, more detailed
image here: 180kb jpg
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
|
| Image Credits: |
Acquired and processed by
the Canada Centre for Remote Sensing |
|
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".
|
