Although I full rendered the world, only a small amount of it shows up. Is there a way to make the entire map show. Although my entire map is water based on the map it only shows small patches of land and water.

how did you pregenerate the map? dynmap only renders chunks that exist on disk.
And if you upgraded the map from a older version to the new one MC only converts chunks on load and dynmap doesn't see unconverted chunks. Spigot has a launch parameter to fully upgrade all existing chunks

get worldborder plugin and run /wb fill , then /wb trim