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Sydenham House Owen Sound, ON [Select refresh to update this page.] |
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| 5/20/12 |
Live Weather |
| Conditions at 2:20pm |
Click on the image above for a time-lapse movie of the past 24 hours.
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Temperature |
30.5°C |
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Beaufort Scale |
Light Breeze |
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Comfort Level |
Warm |
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Barometer |
Steady |
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Cloud Base |
4631 |
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| Today's Highs and Lows | |||
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High |
30.7°C |
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Low |
11.5°C |
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Peak |
24km/hr |
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| Astronomical Data | |||
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Sunrise |
4:50am |
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Sunset |
7:50pm |
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Moonrise |
4:31am |
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Moonset |
7:49pm |
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| Weather Radar | |||
| Summaries |
| Highs and Lows |
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Three-day Forecast |
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| Mon | Tue | Wed |
| T-storms | Chance Rain | Sunny |
| 28° | 16° | 21° |
| 9° | 8° | 13° |
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Links & Tools |
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| Camera Calendar View | ||
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Snow Gauge (beta) |
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Snow Data Acquisition: This is, perhaps, the only autonomous real-time snow gauge currently operating on the internet. It employs a Linksys WVC200 network camera pointed at a length of 2½-inch PVC pipe painted fluorescent orange. The pipe is held upright by an outdoor umbrella stand with its sleeve painted orange to match the PVC pipe. To facilitate the recording of data at night, a length of LED rope lights runs down the side of the pole. It is held about four inches out from it by a combination of plumbing fixtures and improvised standoffs. The lights are secured to an aluminum yardstick by wire ties. This maintains the lights in a straight line, blocks the glare of the lights from the camera, and acts as a means of visually verifying snow depth. An image of the pipe is recorded every ten minutes and processed by RoboRealm software, which is designed to provide vision capabilities for robots. Each image is filtered in the software so that only the florescent orange part of the image is visible (see bottom images at right). The software then draws a line from the top of the fluorescent area to its bottom, and measures the length. This value is processed by an algorithm written in VBScript that translates image pixel data to real-world snow depth in centimeters. The data is written to a CSV file and used by Image Salsa weather image processing software, and another VBScript program, to import and compose the overlays on the weather image at the top of this page. Data is accurate to within 2.5 cm (one inch). |
The time-stamped image above represents the latest good data recorded by the snow gauge. To be considered good data, the same value must result from two consecutive image reads ten minutes apart. The numbers in the top-right of the image represent (in pixels) 1) the length of the visible pole; 2) the distance from the bottom of the image to the bottom of the visible pole (also shown as the green dot); and, 3) the distance from the bottom of the image to the top of the visible pole.
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Snow Gauge 2.0 December
12, 2009: This year a number of improvements, most notably the
relocation of the gauge to the deck, which accomplished several things.
First, it provided a less protected, and therefore more representative
exposure to snowfall. In addition, it was found that the patio stones
absorbed heat and snowcover would not be sustained like it is on the
deck. Just as significantly, the move permitted the relocation of the
camera to the south of the pole, which reduces glare from the sun and
provides a more reliable image on sunny days. But because we have no North-facing windows, it was
necessary to build weatherproof enclosure and keep the camera
temperature above rated operating specifications. This enclosure
comprises a Coleman cooler to keep the snow off the device. I opted not
to enclose it hermetically because of problems with condensation.
Instead, I wound an electric water pipe antifreezing device around the
bottom of the box. This should come on and warm the box sufficiently in
cold weather – if it doesn’t melt the plastic sheath and
catch fire first. Protection from the wind and the heat from the camera
transformer inside the box keeps the temperature in it about five
degrees above ambient. The camera operating temperature is rated at
zero degrees Celsius. Thanks to the moderating effect of Among other refinements this year: Roborealm tweaking to
include temporal modules that even out rapid changes in pixel intensity
and several other minor adjustments. As a result, the image is more
stable and there is less flickering of the readings. The downfall this year, if there is one, will be the
fluorescent paint used on the pole. This colour is good because it
doesn’t occur in nature and is unlikely to crop up on the image
during weird lighting conditions to cause interference. Last year there
was significant fading – to the point that Roborealm had
difficulty at the end isolating the ends of the pole. I have since read
that ultraviolet light degrades fluorescent paint. I changed the paint
manufacturer this year with the hope that it will mitigate the problem,
but I can already see some signs of fading. Next year there will have
to be significant experimentation with paint colours and brands –
not a task I look forward to. I will be enjoying my Snow Gauge from sunny
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The pole stands about 10 feet from the camera unit.
Sun is the camera's enemy. It produces glare and destabilizes the image on sunny days. To prevent this, the camera needs to face north, which makes the sun travel behind it and shine directly on the pole. |
| Season Summary April 12, 2012: The winter that never was… record-setting high temperatures, negligible amounts of snow, and patchy gauge operation all conspired to yield relatively few readings this year. Maybe next winter we’ll have better luck. | ![]() |
| Season Summary March 27, 2011: More snow than the previous year; larger, more pronounced snowfalls. 33,000 data points with an 82% good read rate. | ![]() |
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Season Summary March 14, 2010: Not much snow this winter, but the gauge performed flawlessly, producing nearly 30,000 data points with an 86 percent good-read-rate. |
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