Meters per minute of longitude

In the morning the class worked on finding Binky. This term Binky was at North 6° 54.570', East 158° 09.337'. Binky was hidden in the tall grass at the bottom of a tree down a slope off the edge of campus. This led naturally to the question of just how close to Binky could the coordinates have put a searcher? Put another way, how far is 0.001 arc minutes in meters?

Laboratory seven sought to determine the conversion factor between meters and minutes. The conversion factor would allow one to convert 0.001 arc minutes to meters.

Julie-Ann Ardos with the surveyor's wheel

Spring 2015 I sought to decrease the error by using a more precise conversion between feet (measured by the surveyor's wheel) and meters. Rather than use 100 clicks on the non-metric surveyor's wheel as 30 meters, spring 2015 I went ahead and converted each 30 meter interval into feet: 98, 197, 295, 394, 492, and 591 feet. I then rolled the wheel while holding a crib sheet with the equivalents in feet.

Barry Diopulos watches the latitude in the rain

This summer I decided to run with the original 100 click design which is known to have about 1.5% error out at 600 feet. The 100 click rule (100 feet) allowed a student to take over the surveyor's wheel work.

Julie-Ann, wet but undeterred

The class started at 158° 09.600' east which made for easier subtraction of the start longitude. Visually the change in arc minutes is also easier to comprehend. 158° 09.000' would be better yet, but that is not on campus. This term a start at the "second palm" put the latitude at 6° 54.570'

Joemar Wasan, Barry, and Sharon Mualia watch their GPS units. Rain is falling harder, but they are undistracted



The rain chased away all but five students by the time we reached 600 feet (roughly 180 meters): Julie-Ann, Pelma Dilipy, Joemar, and Barry.


Sharon shows Pelma and Julie-ann her GPS readings


Barry and Joemar at 600 feet


The results of the data are close to the published value of about 1842 meters per minute. The slope is within 3% of the true value. 



On Friday the class took the midterm. Binky was there at the midterm.
Location: College of Micronesia (National Campus), Palikir, Pohnpei, Micronesia

Comments

Post a Comment

Popular posts from this blog

Plotting polar coordinates in Desmos and a vector addition demonstrator

Image
In an earlier post I noted that Desmos did not directly plot polar coordinates. Not only was I incorrect, but Desmos responded to my blog to correct me! Although I had at some point seen that one could define a function f(x)=3x+5 and then have Desmos calculate f(6), I had not absorbed how this might be used to plot polar coordinates. The above works beautifully . Realizing that I could effectively program Desmos, I applied this thinking to demonstrating how to add two vectors when given the magnitudes m and the direction angles theta. The graph calculates the i and j components for the two vectors and then adds the vectors, graphically displaying the result while also providing information on the magnitude and direction of the vector sum. m1 and theta1 are the magnitude and direction angle for one of the two vectors, m2 and theta2 are the magnitude and direction for the other vector. All four are dynamically interactive and can be changed. The diagram purports to illustra...
Read more

Traditional food dishes of Micronesia

Image
Clara, Jennette, and Joanie presented ground hard taro cooked in an umw, effectively a hot rock oven. Pohnpeian: rotama. Pingelapese: sero. Mwoakillese: rodma. Mortlockese: Amahd. Kosrae: rodoma. After cooking in an umw the rotama is pounded with the petiole of a palm frond. Rotama is made from hard or swamp taro, known as mwahng on Pohnpei, mweian on Pingalap, pula in Mortlockese, and pahsruhk on Kosrae. In traditional times on the outer islands the women had primary responsibility for tending the taro while the men handled fishing and climbing tasks. Joesen and Noeleen presented fermented breadfruit from the outer islands of Yap such as Woleai and Eauripik. The raw ingredients were actually brought in from Yap, Noeleen prepared the maare.  The leaf wrap is ti leaf - Cordyline fruticosa. Pauleen, Barnson, Trisha, Verginia, Con-ray, and Maylanda from Kitti, Pohnpei brought in mahi umw, koahpnoair koakihr, and uht sukusuk. Above is breadfruit umw, mahi umw, o...
Read more

Setting up a boxplot chart in Google Sheets with multiple boxplots on a single chart

Image
The  Google Statistics  add-on for Google Sheets can display multiple boxplots in a single chart. The key is the layout of the data. One column should be the variable by which the data is to be grouped, the other column should be the data to be box plotted. Set up the Statistics add-on with the data to be plotted as the variable, and the grouping column as the "by" variable. In this image I had deselected all but the boxplot option, the result was the appearance of the Moment, Standard errors, and Confidence intervals options. The default is apparently a 95% confidence interval for the mean. The result is multiple boxplots on a single chart with a common scale. The new tab that is created also quotes 95% confidence intervals for the mean. Note that as of 2018 the Google Statistics add-on cannot be found by search in the add-ons. In addition, as of May 2018 the add-on no longer verifies, possibly due to the add-on not having been updated since August 2017. One may ha...
Read more