Hi,

I am new to doing spatial analysis.  I am interested in trying many things
in R, but one of the first things I would like to do is plot all of my lat,
lon points in a csv file within a window defined by a shapefile.

I have read in the shape file by doing the following:
border <-readShapePoly("shapefiles/maryland.shp")
plot(border, border="red", las=1)  # plot confirms correct shape
border <-as(border, "owin")

However, once I try to do:
data_ppp <-ppp(data$Latitude, data$Longitude, window=border)

I get the error that:
In ppp(data$Latitude, data$Longitude, window = border) :
  523461 points were rejected as lying outside the specified window

I realized that the coordinates are completely different.  The coordinates
in my data file (i.e. my csv file) are traditional GPS coordinates (e.g. 39.17
or 76.37).  The shapefile however has x,y values such as 1416813.54262877
or 561125.546602725. I am not familiar with what type of coordinate system
those values use.

How can I change the coordinates in my csv file to match the same system as
my shapefile or the other way around--i.e. to get my shapefile to have
similar coordinates as my csv file?

Any help would be appreciated.

Thank you.

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