Abstract:Surface modeling is the process of plotting a natural or artificial surface through one or more mathematical equations. Modeling land surface modeling is a particular case of the areas that need to be taken of the specific issues related to the representation of the earth or parts of it. Digital model of an object or phenomenon, consists of a collection of data stored systematically (database) describing a three-dimensional coordinate system, arbitrary or particular characteristics of the object or form their states / achievements phenomenon (conversion as digital image) and allow adequate computer programs deduction form and characteristics of the object or phenomenon achievements Star new points. Digital model of the terrain is a "tool" information consisting of field data and software is a key component of a GIS. DEM consists of an ordered set of planimetric position information and share the points that describe the spatial configuration of the structures carrying relief and reconstruction surface facilitates their new points. Development of a digital terrain model and its future use involves the following steps 1. DTM GENERATION consisting of initial data acquisition and digital model building. This step represents a fundamental stage because the existence of errors introduced during data acquisition will be found in the DTM and will jeopardize the whole process of spatial analysis. Generating digital terrain model refers to the data acquisition module, the actual realization of the model by different interpolation methods and the choice of data structure representation (raster or TIN). 2. HANDLING DTM: correction of errors and possibly update the model, filtering operations, combining multiple sources or models from different periods, the transformation model structure (TIN - raster and vice versa); 3. INTERPRETATION DTM: analysis model and extracting useful information;April. 4. VIEW DTM: DTM graphical rendering (representations2D, 3D, animation, etc..), Closely related to the previous stage; May. 5. OPERATION DTM: developing specific applications for the desired range.

Key words: three-dimensional,GIS, planimetric, land surface modeling.

Presentation: oral