Hi guys: I run the fellowing example with IDL 8.2.3 and find the speed of zoom and translate of map with mouse is very slow. But after I remove the "mp_bound.thick = 2" or just set "mp_bound.thick = 1", the speed is faster. So why? Very thanks! In addition, this problem just happen for contour over map. PRO test_map ; Define the data by reading the image into IDL, ; creating the daymap variable to hold the data. READ_JPEG, FILEPATH('Day.jpg', $ SUBDIR=['examples','data']), daymap ; Define the latitude and longitude data for the contour. longitude = FINDGEN(360) - 180 latitude = FINDGEN(180) - 90 cntrdata = SIN(longitude/30) # COS(latitude/30) ; Display the global image. map2 = IMAGE(daymap, $ LIMIT=[-90,-180,90,180], GRID_UNITS=2, $ IMAGE_LOCATION=[-180,-90], IMAGE_DIMENSIONS=[360,180],$ MAP_PROJECTION='Mollweide') ; Draw the contour on top of the map image. cntr2 = CONTOUR(cntrdata, longitude, latitude, $ GRID_UNITS=2, N_LEVELS=10, RGB_TABLE=34, /OVERPLOT) mp_bound = MAPCONTINENTS(/COUNTRIES) mp_bound.thick = 2 END