load coast;
latlim = [-80 80];
lonlim = [0 360];
axesm('MapProjection','mercator',...
      'MapLatLimit',latlim,'MapLonLimit',lonlim,...
      'MLabelLocation',30,'MLineLocation',10,...
      'PLabelLocation',30,'PLineLocation',10,...
      'LabelFormat','signed');
mlabel; plabel; framem;
plotm(lat,long,'LineWidth',1,'Color','blue');