S-Pol Antenna Camera Image Viewer

S-PolKa RICO, Codrington, Barbuda
Nov 2004 - Jan 2005

Usage

Make your selections in the frame to the left. Submit your selections when complete. Loading of image info might take a little while. Be patient.

Your browser must allow JavaScript. In the case of IE 6.0, you must allow "Active Scripting".

You may not select a time period that spans more than two partial clock hours (you can process one minute through 1 hour 59 minutes, as long as you do not request images from more than two consecutive hours).

Be sure to set your connection type. Connection speed is important, and improper setting will cause dropped frames. There are a lot of images, and viewing is best from DVD disk or local hard disk (especially internal disk).

Be aware that not all browsers are compatible with this tool.

Be patient while image info is being filtered. The IE browser is very slow for this operation. The Mozilla/FireFox browsers are much, much faster. (IE is also slower than Mozilla in browsing the images).

Best if you display is at least 1280x1024 pixels.

Miscellaneous Project Details

• The valid range of dates/times for this image archive are approximately 26-Nov-2004 through 25-Jan-2005. Some periods are missing.
• Images are for daylight hours, only. Visual characteristics of clouds vary greatly with viewing angle and solar illumination angle.
• The time as shown in the upper left corner of the Antenna Camera photo is not correct. The Antenna Cam clock was not in sync with the network clock, and the antenna cam clock drifted (maximum offset of 18 seconds by the end of the project). Corrections have been applied, and the correct time is shown in the text button below the photo.
• There are approximately 5 million images in the full data set
• The scan image is active: clicking on an echo will show the photo corresponding to the direction of that echo. (This feature does not yet work with IE browsers; see Compatibility, below).
• This is a real-world data set. There are features in the data that may cause the browser to glitch or hang. Problems may be caused by incompleted scans, dropped beams, or just a bad match between image times and beam times. Overall, the browser works, but glitches are not unusual.
• Images and code packaging issues are undecided. Options being investigated are: in daily units for review on DVD; sub-daily units for ftp download; full data set on USB disk. Total data set size is about 120 GB, or about 2 GB per day of images.
• Overall pointing is accurate to better than 1°. For reference, the free-standing radio tower east of Codrington is at 14.4° azimuth (this tower is barely visible behind a large bush); the small white GPS antenna on the roof of S-Pol is at 54.4° azimuth (the GPS antenna is visible only in the lowest SUR tilt, 0.5° elevation).
• Some features of the code are "unpolished" -- the interface could be nicer, but this is a trade-off between my time, and how widely we might expect this package to be used. Changes/improvements can be made upon request.

Compatibility testing

Old browsers are not supported. You should not be using an older browser due to security concerns. Different browsers are slower or faster than others. FireFox under WinXP was the fastest; IE is slowest (all tested with files on local harddisk, or 100BaseT-networked disk).

This tool has been tested and found to work with the following newer browser/operating system pairs:

• Mozilla 1.7 / WindowsXP Professional
• IE6.0 / WindowsXP Professional (echo tracking is incompatible in IE)
• FireFox 1.0.7 / WindowsXP Professional
• Opera 8.5 / WindowsXP Professional

• FireFox 1.5 / RedHat Linux
• Mozilla 1.7 / RedHat Linux

I have not sufficiently tested this tool under Max OSX and its browser. The Safari browser hung on its last test, but the code has been changed since that test. If you try Safari, let me know how it does.