You can simply use the contour or contourf or imagesc function to do that.
Let us start with the random data.
temp=randi(5,50,40)+273;
lon=[50:100];
lat=[0:40];
imagesc(lon,lat,temp)
load coastlines
hold on
plot(coastlon,coastlat,'r','linewidth',2)
set(gca,'Ydir','normal')
colorbar
colormap(flip(bone(8)))
Let us take satellite data to plot the data on map. I am taking TRMM precipitation data as a sample:
figure
filename='trmm_sample_data.txt'; % Attached
% This is a netcdf file, but I have replaced the file extension from .nc to .txt file
% in order to attach .nc file here in the answers.
lon=ncread(filename,'lon');
lat=ncread(filename,'lat');
pcp=ncread(filename,'precipitationCal');
imagesc(lon,lat,pcp)
hold on
plot(coastlon,coastlat,'r','linewidth',2)
set(gca,'Ydir','normal')
colorbar
colormap(jet(10))
axis([75 90 15 25])
If you have the shapefile of caostlines, or state bundaries, you can load it using shaperead.
