[R] [FORGED] find numbers that fall in a region or the next available.

[Rolf Turner]

On 03/02/16 11:04, Alaios via R-help wrote:
> Dear all,I have GPS coordinates (one vector for longitude and one for
> latitude: GPSLong and GPSLat) of small are that is around 300meters X
> 300 meters (location falls inside UK).At the same time I have two
> more vectors (Longitude and Latitude) that include position of food
> stores again the UK I would like to find within my 300x300 square
> area which as the food stores that fall inside.I thought to try to
> find which of the Longitude of the food stores fall inside my area. I
> tried something the below
>
> Longitude[Longitude>(min(GPSLong)-0.001)&&Longitude<(max(GPSLong)+0.001)]
> but this returned me zero results.The next option would be the code
> to return me at least the place that falls outside but still is close
> to that region.'Do you have any idea how to do that and not fall back
> in the time consuming look at each element iteration?
> I would like to thank you for your reply


You could make use of the distfun() function from the spatstat package. 
  Represent your "small area" as an object of class "owin".  The 
longitude and latitude coordinates will be treated as if they were 
Euclidean coordinates, but over distances of the order of 300 metres 
this should not matter much.  You could of course convert your long and 
lat coordinates to metres, using some appropriate projection, which 
might make more sense in your context.

cheers,

Rolf Turner

-- 
Technical Editor ANZJS
Department of Statistics
University of Auckland
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