The above sea level height-data for this model is taken from the Space Shuttle Radar Topography Mission dataset (http://dwtkns.com/srtm/) and the seafloor is from the NOAA's ETOPO1 dataset (http://maps.ngdc.noaa.gov/viewers/wcs-client/).
After combining the two heightmaps I displaced the terrain onto a high-resolution plane and added surrounding walls exactly in line with the sea level. Once the sea-floor was painted, I poured liquid resin onto the model up to the walls. After the resin had set I painted the islands. The model is painted with acrylics and inks.
I printed with 3 bottom layers and 4 top layers, to ensure a smooth sea floor.
Using any hard-setting liquid resin, fill the model up to the sea level (the side walls are in-line with the sea level) to create a transparent ocean.