r - Transform coordinates from NOAA

I use data from NOAA for some analysis in R and I want to transform coordinates to EPSG:54004 or something useful.

There is something what they write about their coordinates.

...    

POS: 29-34 
 GEOPHYSICAL-POINT-OBSERVATION latitude coordinate 
 The latitude coordinate of a GEOPHYSICAL-POINT-OBSERVATION where southern 
 hemisphere is negative. 
 MIN: -90000 MAX: +90000 
 UNITS: Angular Degrees 
 SCALING FACTOR: 1000 
 DOM: A general domain comprised of the numeric characters (0-9), a plus 
 sign (+), and a minus sign (-). 
 +99999 = Missing 


POS: 35-41 
 GEOPHYSICAL-POINT-OBSERVATION longitude coordinate 
 The longitude coordinate of a GEOPHYSICAL-POINT-OBSERVATION where values west from 
 000000 to 179999 are signed negative. 
 MIN: -179999 MAX: +180000 UNITS: Angular Degrees 
 SCALING FACTOR: 1000 
 DOM: A general domain comprised of the numeric characters (0-9), a plus 
 sign (+), and a minus sign (-). 
 +999999 = Missing

... 

And my problem is, that I can't transform this coodrinates correctly. I use this R command:

    sc <- cbind(st$LAT, st$LON)
    ptransform(sc/180*pi, 
            '+proj=latlong +ellps=sphere',
            '+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs')

But coordinates are somehow wrong as you can see. The points should be in borders because they are meteostations from this countries. .

Answer

I solved the problem, it was in input to ptransform function in R.
Instead sc <- cbind(st$LAT, st$LON) I have to use sc <- cbind(st$LON, st$LAT). Then as you say I have to use EPSG:4326 as input CRS and EPSG:3857 as destination CRS. And the transformation with this command.

    tr <- ptransform(sc/180*pi, 
            '+proj=longlat',
            '+proj=merc')