Raster images or surface are more designed for analytical purposes. A raster image constitutes of over thousand of cell each containing values that can be analyzed or used in algorithms. Triangular Irregular Networks or TIN's are more used for surface display purposes. TIN's are vector based representations of the physical land surface made up of irregular distributed nodes and line with 3D coordinates (x,y and Z) that are arranged in a network of non-overlapping triangles.
TIN's can basically be created from various data formats such as contour lines, sample points, raster images, any data containing coordinates (x,y) and the most important 3D values (z) which in most cases are depth or height values.
I will derive data contained in this raster to create a 3D TIN model of the project