February 20, 2008

HPWREN camera observes more than four years of post-fire plant regrowth

Shortly after the 2003 Cedar Fire, HPWREN provided a high-speed wireless data connection to the CDF fire camp in La Cima, which is situated between the Cuyamaca and Mt. Laguna mountain ranges, and an environment that was devastated by the fire. For about a year, until phone lines were re-established to La Cima, the connection also provided for voice/FAX connectivity.

An incidental benefit of the connection has been a fixed digital still camera, which is monitoring the post-fire environment in that area since the fire more than four years ago. It was added to a hilltop-relay which had been installed in 2003 to reach the camp. The camera is a 1288x968 pixel resolution IQeye3 camera, set up to do pixel-based motion detect, as well as collecting an image every ten minutes. The regular image collection has already resulted in more that 140,000 images. Occasionally, especially during fires, a higher image collection frequency is used to create time-lapse animations of relatively short durations.

La Cima relay
La Cima hilltop relay site with the camera, after upgrading cabling and replacing the battery in February, 2008.
La Cima relay

To illustrate post-fire regrowth behavior, a subset of the images was taken to create a more than four year time-lapse animation. Specifically, an attempt was made to pick the about "noon" images and display each as three consecutive frames. This resulted in 1437 images, or 4311, which at 30 frames per second would run for more than two minutes. A full-sized MPEG-1 file encoded for 4 megabits-per-second playback amounted to almost 72 megabytes in file size. A 480x368 pixels reduced image size Flash file streaming at about 400 kilobits-per-second came out to be almost 9 megabytes in size.

La Cima 20031231.120400
La Cima 20080129.120001
These images are part of the time-lapse animation. The one on the left is from December 31, 2003, and the right image is from January 29, 2008.

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