Dear Sir/Madame,
I am currently a Masters student at the University of Leicester in the UK
studying MSc Geographical Information Science and am having a bit of difficulty
with the programme R. I am a new user of the programme and don't have any
previous experience in programming. Having looked at various web sites, I
wondered if you are able to help me with some trouble i am having in trying to
write some code for a mathematical equation.
I have attached the question to this email and it can be seen below. The
dataset is a list of polygons with each polygon containing another list within
it, of x and y coordinates.
I would really appreciate it, if you could help me with this question.
Question
Create functions to compute the area, centroid and perimeter of a polygon list
(as in the format of georgia.polys). The formula for the area of a polygon is
A=0.5*?(x? y???) (x??? y?) for i until n-1
where A is the polygon area, xi is the ith x-coordinate of the polygon boundary
(x[i] in R), yi is the ith ycoordinate of the polygon boundary (y[i] in R) -
and n is the number of points used to specify the polygon boundary. The polygon
is assumed to be in closed form so that the x1 and y1 take the same value as xn
and yn.
Hope to hear from you soon.
Yours sincerely
Krishan Mistry
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