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Further Input Features

Interpolate unknown heights of polygon points

In order to generate a proper sequence of a (open or closed) polygon curve (e.g. a terrain contour) additional polygon points may be entered, the heights of which are unknown. CadnaA can determine these unknown heights by linear interpolation.

Proceed as follows:

  • Enter the polygon (e.g. a terrain contour or „contour line“) with the required number of polygon points in order to generate a proper curve.
  • Select on the dialog Polygon: Geometry the option „absolute Height at every Point“.
  • Enter the known absolute heights in column „z (m)“ at the known xy locations.

Note

Move both dialogs, the dialog Polygon: Geometry and the object dialog a little aside in order to see the polygon object in the main window. The currently selected polygon point is highlighted.

  • Select in the table of points, those points one-by-one having an unknown absolute height and press the space bar to delete the default value 0 m.

Dialog Geometry (here of a terrain contour): absolute height zat a polygon point has been deleted using the space bar

Note

Do not use the DEL key, since then the polygon point is deleted from the table.

  • When closing the dialog CadnaA will recalculate the value by linear interpolation.
  • Reopen the dialog Geometry to display the interpolated value/s​​.

Dialog Geometry: The absolute height zwas interpolated between two polygon points.

Alternatively, only the polygon points with known heights can first be entered and then using the editing of polygons (see Polygon Point Mode in the manual „Introduction to CadnaA“) additional points will be entered graphically. Then delete the column "z (m)" of the polygon point list with the space bar the initial value 0 m.

Filling the List of Reference Points

Coordinates can be copied from the geometry of point objects as well as of polygon objects (lines and areas) to a list of reference points for later use. Consequently, there is no need to write down coordinates manually in order to enter them later.

Examples for using a list of reference points include the transfer of coordinates to other objects with transformations (option „Match Points“, see Coordinate Transformation) or the acquisition of coordinates when calibrating a bitmap (see Bitmap Dialog Options in this manual and chapter Import & Calibration of Bitmaps in the manual „Introduction to CadnaA“).

Transferring reference points for point objects

In order to make use of a list of reference point with point objects proceed as follows:

  • Click on button „Geometry“ in the dialog of point objects to open the dialog Point-Geometry.
  • Click on the button „--> RefPoint“ to copy the coordinates of the point to the reference point list.
  • From the subsequent dialog Reference Points, select one of the four available reference points where the data will be copied to.

Dialog Reference Points: reference point 2 is selected

  • Close the dialog Reference Points by OK.
  • By clicking again on button „--> RefPoint“ you can check whether the coordinates have been copied.

Dialog Reference Points: Point coordinates havebeen copied to the reference point 2

Transferring reference points for polygon objects

In order to use the list of reference point list with polygon objects (lines or areas) proceed as follows:

  • On the object‘s dialog click the „Geometry“ button.
  • Double click in the table of polygon points into the row whose coordinates are to be copied as a reference point.

Dialog Polygon: Geometry: After a double click in atable row the dialog Polygon Point opens.

  • Click the button „--> RefPoint“ to copy the coordinates of this point to the list of reference points.

For additional features see section „List of reference points for point objects“ (see above).

Generating Orthogonal Polygons

When entering line-like and area-like objects in the graphics (not for cylinder) right angles between individual polygon sections may be enforced.

Proceed as follows:

  • Select - for example - the object „Building“ from the toolbox.
  • Enter the first polygon point by clicking the mouse button.
  • Now, press the Shift key.

Now, the mouse cursor is trapped in fixed steps of 90 degrees with respect to the preceding polygon section.

  • Click while holding down the Shift key at the position of the next polygon point.
  • Proceed analogously till the last polygon point has been entered.
  • Click with the right mouse button to close the building‘s polygon.

By the last step, the first and the last point of the building are joined automatically and, thus, closing the building‘s polygon.

Note

When drawing rectangles, it is useful to start with the longer side. After having entered the third point for the shorter side, position the mouse pointer on the starting point. Please click on the starting point, to enter the third longer side automatically with it‘s correct length. Close the rectangle by a final click using the right mouse button. This procedure is recommended especially when entering buildings having a rectangular outline.