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MORRIJOS

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    Glendale, CO.
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  1. Eli, thanks for the tips. Can you possibly elaborate on how to estimate and plot the twilight error? I do not have a set calibration period, but rather a stationary breeding period (2-3mos.) for which the BBs are known to have stayed in the same area. Would I plot the known vs. estimated twilights from this period, then extrapolate that to the rest of the data? Does SGAT provide known twilights for some areas and dates, or can this info be pulled from something like the NOAA page? Much appreciated.
  2. Can anybody recommend a "how to" or sample code for using SGAT to describe twilight error, specifically twilight error and its effect on the calculation of an appropriate sun elevation angle? GeoLight's 'getElevation( )' function mentions that SGAT can be used to sensitivity analysis of twilight error. But, I haven't found any documentation for SGAT that is approachable for a newbie like myself. I'm working with tags that were deployed on Mountain Bluebirds and I'm seeing a slight eastward bias in the coordinates calculated by GeoLight, so I'm wondering how much of this bias is due to twilight error or a poor estimate of the sun elevation angle. Where else in the GeoLight workflow could this bias be creeping in? Thanks.
  3. Eldar. Thanks for your reply. Yes, these are custom tags made by Dr. Bridge. I may have to contact him for the sensor specifics... Unfortunately, I do not have a stationary tag to work with; however, the birds are (more or less) known to have stayed in a set location during the nesting season, so I can try to get some calibration info from the first weeks of logging.
  4. I am analyzing data from a couple of light-level geologgers that were attached to Western Bluebirds; I have been going back and forth between analyzing the data with the FLightR and Geolight R packages. Now I'm having trouble picking the tag-specific parameters for the FLightR get.tags.data function. These tags are the sort that record light intensity as values between 0 and 127; they take a light-level reading every minute and average the readings over each 10-minute period. So, I used the log.light.borders and log.irrad.borders as for the Intigeo tags here: https://github.com/eldarrak/FLightR/wiki/setting-up-tag-specific-boundaries. My code: tag.612.FLightR.data <- get.tags.data("tag_612_twilights_TAGS_threshold_5.csv", log.light.borders = log(c(1, 127)), log.irrad.borders = c(-3, 3), saves = c("mean"), measurement.period = 60, impute.on.boundaries = FALSE) Is this correct? And can somebody explain the difference between the log.light.borders and log.irrad.borders parameters?
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