[OR Ss4] Detailed Explanation of the Source Elements of a Terrain Element

I can't find these answered anywhere else.

Coming from an InRoads environment, we had Breaklines, Random Points, Contours, Exterior and Interior Boundaries. In the new Terrain Element, for Source Features, there are Breakline, Boundary (Exterior), Contours and Spot (Random Point) and then there are Void or Hole (one of which is the equivalent to an Interior Boundary) and Island.

While I can guess that an Island is a terrain area withing some type of hole, I don't know if that "hole" is a hole or a void?

I do believe that this type of information needs to be added to the Element Template or Terrain Element topics.

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  • Taken from ORD help files:

    Feature Type Description

    Spot or Spot Elevation

    Points (with X,Y,Z data) that have no functional relationship to any other point. Random survey shots in open terrain would be an example of random spots. Point elements such as cells, circles, and text strings are typical MicroStation elements used to graphically define spot elevations. Lines, line strings, and other longitudinal elements are equally valid. The software creates a spot elevation for each vertex of each longitudinal element.

    Break Line

    Breaks are used to designate linear features such as edges of pavement, ditch bottoms, ridges, etcetera where an abrupt change of slope occurs. Any longitudinal element may be defined as a break line. Triangles will not cross a break line in the terrain model.

    Soft Break Line

    A soft break line is a break line, however, if it crosses a break line, it will not affect the triangulation and is ignored.

    Contour

    Element or set of elements of the same elevation. Contours may be used as source data to generate a terrain model, or may be computed (drawn based on terrain model). Contour interval is the elevation difference between two adjacent contours.

    Hole

    An area defined by a closed shape that demarcates a region where the current terrain is ignored and the underlying terrain is utilized.

    Boundary

    The external boundary of the surface.

    Drape Boundary

    A surface boundary that determines its elevations by draping on the underlying surface.

    Void

    An area defined by a closed shape that demarcates a region of missing data or obscure areas. No point or break data located within the void area is utilized and no triangles are created inside the void areas. The Void coordinates are included in the triangulation and void lines between successive void coordinates are inserted as drape lines on the surface. Therefore, they do not change the slope or elevations of the surface.

    Drape Void

    An area defined by a closed shape that demarcates a region of missing data or obscure areas. No point or break data located within the void area is utilized and no triangles are created inside the void areas. In the drape void, the void coordinates are not included in the triangulation. Voids are inserted post triangulation. The void coordinates and lines are draped on the terrain model surface. Even though a user must provide an elevation for Drape Void vertices, the user elevations are changed to the elevation of the terrain model surface at the XY Drape Void coordinate position.

    Break Void

    An area defined by a closed shape that demarcates a region of missing data or obscure areas. No point or break data located within the void area is utilized and no triangles are created inside the void areas. It differs from Voids and Drape Voids in that it utilizes the vertex elevations of the graphical element, while the void lines between successive void coordinates are inserted as break lines. Therefore, break voids change the slope and elevations of the surface.

    Island

    An area defined by a closed shape that demarcates a region of data wholly within a void. Example, islands in the middle of rivers, lakes, etcetera.

    Answer Verified By: caddcop 

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  • Taken from ORD help files:

    Feature Type Description

    Spot or Spot Elevation

    Points (with X,Y,Z data) that have no functional relationship to any other point. Random survey shots in open terrain would be an example of random spots. Point elements such as cells, circles, and text strings are typical MicroStation elements used to graphically define spot elevations. Lines, line strings, and other longitudinal elements are equally valid. The software creates a spot elevation for each vertex of each longitudinal element.

    Break Line

    Breaks are used to designate linear features such as edges of pavement, ditch bottoms, ridges, etcetera where an abrupt change of slope occurs. Any longitudinal element may be defined as a break line. Triangles will not cross a break line in the terrain model.

    Soft Break Line

    A soft break line is a break line, however, if it crosses a break line, it will not affect the triangulation and is ignored.

    Contour

    Element or set of elements of the same elevation. Contours may be used as source data to generate a terrain model, or may be computed (drawn based on terrain model). Contour interval is the elevation difference between two adjacent contours.

    Hole

    An area defined by a closed shape that demarcates a region where the current terrain is ignored and the underlying terrain is utilized.

    Boundary

    The external boundary of the surface.

    Drape Boundary

    A surface boundary that determines its elevations by draping on the underlying surface.

    Void

    An area defined by a closed shape that demarcates a region of missing data or obscure areas. No point or break data located within the void area is utilized and no triangles are created inside the void areas. The Void coordinates are included in the triangulation and void lines between successive void coordinates are inserted as drape lines on the surface. Therefore, they do not change the slope or elevations of the surface.

    Drape Void

    An area defined by a closed shape that demarcates a region of missing data or obscure areas. No point or break data located within the void area is utilized and no triangles are created inside the void areas. In the drape void, the void coordinates are not included in the triangulation. Voids are inserted post triangulation. The void coordinates and lines are draped on the terrain model surface. Even though a user must provide an elevation for Drape Void vertices, the user elevations are changed to the elevation of the terrain model surface at the XY Drape Void coordinate position.

    Break Void

    An area defined by a closed shape that demarcates a region of missing data or obscure areas. No point or break data located within the void area is utilized and no triangles are created inside the void areas. It differs from Voids and Drape Voids in that it utilizes the vertex elevations of the graphical element, while the void lines between successive void coordinates are inserted as break lines. Therefore, break voids change the slope and elevations of the surface.

    Island

    An area defined by a closed shape that demarcates a region of data wholly within a void. Example, islands in the middle of rivers, lakes, etcetera.

    Answer Verified By: caddcop 

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