The price.- There is not any professional program on internet like this, and you can get it without any effort. I think this could be a handicap because it's dificult to believe, but it's true!; try it and you'll surprise you. Professional.- It's not only a program to calculate a delaunay triangulation but you can insert break-lines to get a representation of the real terrain. In this thecnical document, written by Severin Cazanescu for a conference, we can learn how LanDTM apply the delaunay triangulation principles. History.- The first version of this program came on to the market in 1992 and there are more of 3000 professionals working with it, civil engineers, architects, foreman builders, surveyors, mathematics, etc. Quick, Unlimit points and reliable.- I've tried the program with 1000000 of points and It had'nt problems to calculate the triangulation. The program is more slow when you have too many break-lines, (more of 20000).

Flexibility.- Usually, the programs have tools to edit, on the drawing the calculated triangulation. This is good because you see the modifications in real time. LanDTM has these tools, 'insert line', 'change edge', 'insert point', 'delete triangle', etc, which they are in a Tool Bar easy to handle. The contouring and triangulation are drawn again while you use these tools. But, that's not all, given the best feature of LanDTM is that you can exit the program and to edit the triangulation lines like you want with all the power of the CAD edition tools, deleting, inserting, "intersecting", changing elevations, triming, extending, etc. If you are in a CAD you must to take advantaje of it. When you finish the edition, simply import the lines, and the program will not have problems to create, again, the new triangulation.

Safety.- A good program to calculate DTMs must have a system to find errors. The most tipical error is that you have a line with elevation 0.0 or a line don't have a support point. When you edit the triangulation by hand it's very common to make errors. So LanDTM shows graphically the triangles without adjacents, (without neighboring), paint them with other colour to see them quickly, and the only triangles without adjacents should be the triangles they are in the drawing external zone, if you see triangles without adjacents in the center of the working zone it means there is an error. Other way to find errors is drawing the triangulation lines and changing the view point to check if there are "rare" lines. We must take advantaje the CAD power and to use it, always, for our own benefit.

Multitask.- You can open until five instances of the program and work with a different DTM in each. Only, write "LanDTM" on the command line and you'll see other 'LanDTM' window. Smoothing test.- A profesional program for civil engineering it's not profesional if It doesn't have a smoothing test. When you make the smoothing of the contour lines, after you must check if the resulting smoothing curves intersect between them and if this is appreciable or not. LanDTM has a tool, to run in background, with which you'll be able to see all the intersections between curves, and It'll draw a circle in the intersections points in order that you can decide if to correct the curves, don't touch them because it's not appreciable or to make the smoothing contour lines with differents parameters.

Volume calculation.- You can calculate the volume between two DTMs. There are two ways to get it. The first, and more easy, is to make a "grid" for each DTMs and to calculate the volume for the sum of each paraleliped formed. This is done with a single order, "Tools/Make 3D grid", where you can select between to calculate a single grid of points or a grid of points which elevation is the difference between two DTMs. After, you can use "Tools/Grid Volume" option to get the volume in cubic meters. The second, and more accurate, is to calculate the volume between two triangulations, projecting each of them in the other and calculating, as result, a new triangulation. It's a litle more complicated to explain but the calculated volume is the exact. This option is in the main menu of the "graphic dialog box", "Applications/DTMs intersection". After to make the DTMs intersection you can use "Applications/Model volume" order in the main menu to get, in cubic meters, the total volume between them. Fill and cut.- With the volume calculation, the resulting points have, as elevation, the elevation difference between each models with you create them. So, we can draw CAD solids, "SOLID", with differents colours so that they show us the fill and cut zones. With the points grid you'll have to calculate, previously, the triangulation to can draw the solids, "SOLID" entity in the CAD. This is a map very useful in civil engineering.

Dinamic longitudinal profile on DTM.- According a drawn a polyline in the CAD on a DTM you can use "Applications/Dinamic profile on DTM" option and you'll see as a graphic, with a longitudinal profile, goes changing in real time according you edit that polyline. Slopes according a poligon.- Many times you have a project where you must place a plain in the terrain to can make a built, parking, platform, etc, and you must level it. This leveling, you want to make, needs slopes in the limits of the plain. With this tool you'll be able to draw the lines of the resulting slope, of cut and/or fill.

Import/Export.- Given the program only allows import/export drawn entities or Protopo's coordinate files in ".CRD" format, you can think the program needs a good way to import/export files, it's for that I've included with LanDTM program other program to import/export files, at any format, to Protopo '.CRD' or AutoCAD '.DXF' files. The program is called ProLink and with it you'll be able to create any file in ASCII format you want and to make it compatible with "Protopo CRD" or "Autocad DXF" files.