uSMART Mapping Tools

SLines (Break Lines) and TIN

SLine is a word derived from Survey Line. SLines are commonly referred to as break lines and TIN lines. SLines are used for interpolation purposes and can be placed manually or may be automatically generated from user defined design file elements. Once established, SLines assist in contour placement, section extraction, regular grid D.T.M. generation, height tracking, height transformation of design file data, theme creation and orthophoto creation.

Automatically generated SLines are accomplished by using the Delaunay Criterion for triangles. Once these triangles are determined however, only individual sides are placed as SLines in the design file or mass data file. In this way, these SLines can easily be edited and manipulated without all the limitations imposed by using triangles.

A brief overview of the SLine routines follows:

Height ThemeManual SLine: Place
Manually placed SLines are normally break lines. These may be mapped before the TIN creation or added afterwards and the TIN will automatically update taking the new line into consideration. Break lines are always "kept" in uSMART i.e. they will never be removed during the TIN creation.

SLine Place: From Linear
With this mode the SLines are generated from detail already placed or while placing linear features. As a fair amount of detail generally represents so called "break lines", this method can be used to quickly generate break lines from existing detail such as roads, watercourses, embankments, etc. The existing detail used to generate the new SLines is not changed in any way; however a new series of SLines is generated which follows, or closely follows the existing detail. After this is done the areas between the break lines can be automatically triangulated using the Automatic mode and you will find that only limited editing of the SLines will be required to generate automatic contour lines.

SLine Place: From Structures
SLines are generated from structures already placed. When SLines are created from structures, an SLine is drawn on the "top" of the building and virtually right next to it a second line is placed depicting the bottom of the building. This "bottom" line is drawn according to the surrounding TIN representing the ground. Therefore the surrounding TIN must accurately represent the ground area around the building. True orthophotos (where the pixels have been replaced in the occlusion/dead areas from other images) may be created using these TIN lines created from the structures.

SLine Place: Automatic (TIN)
For this mode to work SPoints/MPoints and/or SLines must exist in the design, reference or mass data files as these are used to generate the triangulated irregular network. When mapping very large jobs, SLines can be placed in uSMART Mass Data files (using the MDM) which will enable users to have all the lines in one file and not have multiple files with the TIN. The uSMART Mass Data Module can handle billions of lines and may be used to create thousands of orthophotos, contour massive areas and compute volumes between very large surfaces.

SLine Import and Export
Read in lines from other sources e.g. from various ASCII/binary file formats as well as export lines to other sources e.g. to various ASCII/binary file formats. Exports can also be done from a DGN file to the MDM (i.e. an MD file) or from the MDM to a DGN file.

SLine Edit
This routine is used to easily edit many SLines using a variety of methods (modes).

SLine Track Height
This routine is used to determine heights at any point within a TIN. These heights can also be used to place elements at this (determined) height.

D.T.M.
Used to place a regular grid D.T.M., at a user defined spacing from an existing TIN.

Hidden AreasSLine Model
Currently, this routine is only used to create sections from existing topology. Section lines will therefore be drawn on the TIN following the surface of the TIN. A range of smoothing parameters can be applied to the section lines.

SLine Theme
Once placed, the TIN can be used to create thematic displays using various modes such as Height which is used to create a colour theme based on differing TIN heights. Other modes include Slope, Height differences, Direction, Hidden areas, Hidden structure areas and Triangle and Shapes.