show tick label long lat

please, i'm try to plotting total precipitation map. this is my code

ncfile = 'total_precipitation.nc';

%% to read a variable 'var' exisiting in nc file
lon = ncread(ncfile,'lon');
lat = ncread(ncfile,'lat');
tpp] = ncread(ncfile,'tp');

% plot figure
figure
imagescn(lon,lat,tp);
colormap jet
axis image
caxis([0 30])
grid on
set(gca,'GridLineStyle',':')
ax=gca;
ax.FontSize = 7;
ax.GridAlpha=0.5;

% add border
borders('countries','facecolor','r','FaceAlpha',.3,'EdgeAlpha',.3)

%% Indonesia
x1 = 90;
x2 = 150;
y1 = -12;
y2 = 10;
%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% set grid
tickValues = x1:10:x2;
set(gca,'XTick',tickValues,'GridLineStyle','--');
tickValues = y1:3:y2;
set(gca,'YTick',tickValues,'GridLineStyle','--');
% Zoom in:
axis([x1 x2 y1 y2]);

and here is the result

but what i want is to show degree of the longitude and latitude like this one,

Answer 1

[Walter Roberson]

If your longitudes will never be negative (west) then you can use https://www.mathworks.com/help/matlab/ref/xtickformat.html

xtickformat('%d° E')

[Den]

thanks @Walter Roberson, its really helps. but how to use if i have negative value like in my latitude?