Hello everyone,
So I have some latitude coordinates [21.7635   21.7549   21.7462   21.7355   21.7233   21.7181   21.7096   21.7070]
and longitude coordinates [39.1366   39.1315   39.1286   39.1172   39.1133   39.0988   39.0951   39.0891]  with corresponding temepratures [28.5746   28.7729   28.7079   28.6717   28.6379   28.6529   28.7192   28.6996]. 
I'm able to plot these as point marks on a map using geoshow with custom shape file and plotm functions. 
What I need is to use these point values to create a gradient surface so it appears as a shaded fill inside the land area of the shape layer. I attached as an image what I currently get, and the second image sort of what I need to get.