[R-sig-Geo] Warning message: points were rejected as lying outside the specified window

[Barry Rowlingson]

On Sun, May 18, 2014 at 9:29 AM, Rolf Turner <r.turner at auckland.ac.nz> wrote:
> On 18/05/14 14:35, Hossain, Md wrote:
>> Very grateful to Rolf and Adrian for your kind suggestions. Obviously I
>> am going to follow, but it seems there is no quick fix.
>> In the mean time, just wondering, is there anything that I can do
>> with the "map2SpatialPolygons" function. The data came with the
>> long-lat, but no information about how these long-lats are created,
>> i.e., whether using "WGS84" is apropriate or should I try for other
>> options, e.g., for GCS_North_American_1983_HARN. My knowledge in
>> geography is very poor, please help.

Have you done whats been suggested and plotted the points to see *why*
the points are thought to be outside your map? Various things can
happen with data:

 x and y coordinates get swapped
 x and y coordinates are set to 0,0 or  -999,-999 to make missing data
 numbers get typed in wrong
 minus signs in western or southern hemisphere coordinates get left off
 locations are rounded to the nearest 100m, then converted to lat-long
 etc

 the other problem is that the boundary is an APPROXIMATION to the
border. To keep the dataset size small enough, a lot of the wiggly
coastline is approximated by a straight line. If you have points near
the coast then some may end up on the wrong side of the approximated
line. Is that what's happening? Have you plotted the points?

 don't go messing around with projections and datums (which might only
move points by a few metres) until you've had a look at why the points
are outside your polygon.

Barry