uSMART Base Mapping

Transform/Warp

Transform/Warp files using Control Points (CPoints).
Transform files via Geodetic settings.
Transform/Warp the height of elements using a TIN.

The transformation or warping of Design files (*.dgn) or Mass Data files (*.md) using CPoints allows users to convert from a particular coordinate system to another. These systems need not be uniform to each other such as with the new South African coordinate system, which is based on the WGS84 ellipsoid.

In this particular case, coordinates are warped from the old to the new system. The routine then uses the existing trig beacons and town survey marks as supplied by Chief Directorate: Surveys & Mapping. These points are imported into a design file as control points and both coordinate systems are stored for each point. Various configuration options are then available to the user to enable him to effectively warp a design file from one system to the other. Because the actual trig survey data is utilised in the conversion and not an interpolated grid as is the case with many other systems, the results are to the highest degree of accuracy possible.

Routines are also available which dynamically display coordinates in the old as well as the new system, and if the user so requires, the residuals in the calculation can be displayed dynamically as well. Design files can be individually transformed or they can be done in batch mode.

The application can also be used very effectively to convert design files between coordinate systems such as when converting from one "Lo" panel to another or when converting from or to U.T.M. and Gauss Conform map projections.

An important feature of CPoints is the way in which they store their coordinates. Each CPoint has a dual set of coordinates stored known as the primary and the secondary system. The primary system's coordinates are stored as the normal MicroStation element defined by a point (line with same start and end coordinates) i.e. wherever this point lies in MicroStation's design plane determines what the coordinate is on the primary system. The secondary system's coordinates are stored as a "User Data Linkage". This means that they can only be added, viewed etc with the CPoint routines.

The CPoint routines then use these dual sets of coordinates to convert from one system to the other. As both system names are stored with each CPoint, it is possible to have many different systems in the same design file.

It is also possible to convert 2D to 3D by using the "Transform heights by DTM " option. This means that 2D data can be converted to 3D data using an existing TIN. It may also be used to adjust the height of elements to a new height using a TIN.