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Bitmap Dialog Options

Size and position of Bitmap

Alternatively, it has to be specified:

  • the coordinates of the bottom left and top right corners, or
  • the resolution of the map in dots per inch (DPI) and the scale, or
  • reference points, the coordinates of which are known (calibration).

Resolution

With the „Resolution“ option activated, the resolution in dpi when the map was scanned and the scale of the map are required. This method is particularly convenient if only the relative positions of objects matter, and their absolute coordinates are not relevant.

Get geo location from clipboard

This button enables an automatic parsing of map service URLs in order to transform a bitmap object accordingly. When using a map service (see below), select the desired location and then copy the URL (i.e. the web link) to the Windows clipboard.

CadnaA checks the Windows clipboard every half a second for a valid map service URL. If a valid URL is found, the button will be activated. After clicking the button, the bitmap object (its lower left and upper right corner) is set to the position specified in the URL. In case no coordinate system has been selected yet, the Coordinate System dialog appears first (see Coordinate System).

Applicable Map Services

Parsing map service URLs works in the following cases:

  • URL of Google Maps, Bing Maps or OpenStreetMap
  • URL contains latitude/longitude values and zoom level (or elevation in Google)

Note

The resulting size of the bitmap depends on the resolution of the main monitor.

Examples

The following list shows URL examples. The relevant parts of each URL the parser looks for are in bold:

  • Google Maps (preferred):
    • URL: https://www.google.com/maps/@48.0934457,11.3106241,17.75z
    • Note: Zoom is a double with Google and an integer with other services.
  • Bing Maps:
    • URL: https://www.bing.com/maps?osid=d86f552b-3143-4b8f-89e2-7fcb3211d78d&cp=48.093415~11.311326&lvl=19&v=2&sV=2&form=S00027
    • Note: For Bing, the features „Share“ and then „Show full URL“ must be enabled to display the URL in the browser bar.- Spaces within the URL may lead to functional errors (i.e. URL is invalid).
  • OSM:
    • URL: https://www.openstreetmap.org/#map=19/48.09328/11.31179&layers=C
    • Note: Enable on website openstreetmap.de the feature „Permalink“ (bottom right) to display the URL.

Calibrate Bitmap

The „Calibrate Bitmap“ button opens a dialog enabling to enter up to four points with known coordinates on the map. After having entered these points and clicking OK, CadnaA loads the bitmap and prompt you to click onto the reference points in the bitmap being displayed on screen.

Afterwards the calibrated bitmap can be saved using a new filename. However, saving is not compulsory, but advisable with large bitmaps of several megabytes. CadnaA calculates the position of the bitmap and saves it with its correct position.

Save the entered coordinates using a designation name in order to reload with a new import procedure.

Fix Bitmap

As long as the option in the dialog Bitmap|Fix Bitmap is activated, size and position of the bitmap on the screen cannot be modified.

Transparency

The settings for the transparency of a bitmap require that the grid is displayed as the first (bottom) layer (see Layer). The following options are available:

  • none (opaque): In this case, the bitmap has no transparency.
  • old model: For black and white bitmaps (1-bit color depth), the white areas are displayed with transparency. In the case of colored bitmaps, the displayed color results - due to the Windows system - from the additive color (bitwise AND) of the superimposed objects.
  • constant per pixel: The entered constant transparency is applied to each pixel (e.g. 50%).
  • constant + replace white: In this case, the entered transparency is also used, the pure white areas in the bitmap are, however, are displayed globally with transparency.

Note

This option is especially useful after import of bitmaps from GoogleEarth or GoogleMaps in order to show the white border areas generated with rotated bitmaps.

  • from file: In case the bitmap has an alpha channel (transparency value), this is used.

Convert to monochrome (for PDF)

This option offers to convert a colored bitmap into a monochrome bitmap of 1-bit color depth. After conversion CadnaA will prompt you to enter a file name.

Show Bitmap

By the command Bitmap on the Options menu a dialog opens enabling to specify the bitonal scaling of Black & White bitmaps.

Option „Show Bitmaps“

This option enables to activate/deactivate globally the display of bitmaps.

Bitonal Scaling

Select here what kind of bitonal scaling shall be applied with Black & White bitmaps (having 1-bit color depth):

  • Normal: The black level of the first pixel found is used.
  • Favour Black: When a black pixel is found while zooming in, the color black is used.
  • Scale To Grey (default): An average level of grey is used based on all percentages of grey.

The selected option governs the quality of bitmaps displayed on screen when zooming in and out (Zoom +, Zoom -). The option "Scale To Grey" requires a maximum of calculation time.

Note

The option "Bitonal Scaling" has no effect for colored bitmaps.

Bitmaps in 3D-Special view

Loaded and activated bitmaps are displayed in the 3D-Special view (see 3D-Special View) as ground texture. Note that when displaying the grid simultaneously (always shown using mode „Raster, Oversampling“, see Raster, Oversampling), only those grid areas are colorized which are located on a white background color of the underlying bitmap.

Transforming Bitmaps

Bitmaps can be transformed after import as well. Selects the action „Transformation“ on the dialog Modify Objects or as a command from the context menu of the respective bitmap. Please consider that bitmaps can afterwards be transformed with translation only. Thus, settings leading to rotations or shear deformations are not possible.

The entered transformation data will be applied to the corner coordinates of the bitmap. This means that the correction of general or unknown distortions are not possible with this feature. Please use the calibrating procedure described in this chapter for the calibration of bitmaps during import.