mask area outside a shapefile

I am trying to mask data (lon,lat,data) outside a shape file, 'shp1'. I used top use arcgis for masking data but would prefer matlab for these actions.

the code below is non responsive

dx=d(:,:,1); %%%%d is a 80x80 data
lat=(0:0.5:39.5)'; %%%%lat of the data
lon=(60:0.5:99.5); %%%%lon of the data
% lony=lony';
laty=repmat(lat,1,80);
lony=repmat(lon,80,1); %%%%80x80 lon of the data
laty=flipud(laty);  %%%%80x80 lat of the data

%%%read shapefile
  shp1=shaperead('C:\shpfiles\IND_adm0.shp');
  lon1 = [shp1.X]';
  lat1 = [shp1.Y]';
  %%%mask try
  rx = shp1.X(1:end-1);
  ry = shp1.Y(1:end-1);
  mask=inpolygon(lon1,lat1,rx,ry);
  contourf(lon1,lat1,dx);