こんにちは,
f = figure('Position',[100 100 1000 800]); %[left bottom width height]
% 北緯, 東経の領域を表示
worldmap([-89.9,89.9],[-179.9,180]);
land = shaperead('landareas.shp', 'UseGeoCoords', true);
% 海岸線(陸地部分)表示
geoshow(land, 'FaceColor', [0.3 0.3 0.3]);
lat = 35.68956;
lon = 139.6917;
geoshow(lat,lon,"Marker","p","MarkerSize",16,"LineWidth",2,"MarkerFaceColor",[1 1 0],"MarkerEdgeColor","r");