export Export activated points to a file.
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  DESCRIPTION/NOTES
  * Only active points are exported.
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  INPUT
  1 [path]
    Path to output file. The file extension defines the format of the output
    file:
      * 'bxyz'     -> binary format containing ONLY x, y and z coordinates.
      * 'las/laz'  -> las/laz file (only with supported attributes).
      * 'bin'      -> binary format containing x, y, z coordinates AND all
                      attributes defined with the 'Attributes' parameter.
      * 'shp'      -> shape file format containing x, y coordinates AND all
                      attributes defined with the 'Attributes' parameter
                      (Note: the z coordinates of the points can be written as
                      shape attribute by using 'z' as attribute name).
                      For this feature the 'Mapping Toolbox' is needed.
      * 'ply'      -> polygon file format with specified attributes.
      * '???'      -> for any other extension (e.g. '.xyz') a plain text file
                      is created (delimiter = space).
 
  2 ['Attributes', attributes]
    Cell with attributes to export, where each attribute is defined as char. Of
    course, these attributes have to be defined in the attributes structure of
    the point cloud object, i.e. obj.A.
    (This parameter is not considered for bxyz files.)
 
  3 ['ColumnWidth', columnWidth]
    Width of each column. If this parameter is omitted, the output file is not
    column oriented, but values are simply divided by a space character.
    (This parameter is only considered for plain text files.)
 
  4 ['PrecCoord', precCoord]
    Precision of coordinates. It is possible to define either one value for all
    coordinates, or an own value for each coordinate in a 3-by-1 vector.
    (This parameter is only considered for plain text files.)
 
  5 ['PrecAttributes', precAttributes]
    Precision of attributes. It is possible to define either one value for all
    attributes, or an own value for each attribute in a a-by-1 vector, where a
    is the number of attributes to export.
    (This parameter is only considered for plain text files.)
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  EXAMPLES
  1 Conversion to bxyz file.
    pc = pointCloud('Lion.xyz');
    pc.export('Lion.bxyz');
 
  2 Export to binary file with attributes.
    pc = pointCloud('Lion.xyz', 'Attributes', {'nx' 'ny' 'nz' 'roughness'});
    pc.export('Lion.bin', 'Attributes', {'nx' 'ny' 'nz'});
 
  3 Export to a plain text file with a lot of specifications.
    pc = pointCloud('Lion.xyz', 'Attributes', {'nx' 'ny' 'nz' 'roughness'});
    pc.export('Lion.txt', 'Attributes'    , {'nx' 'ny' 'nz' 'roughness'}, ...
                          'PrecAttributes', [5 5 5 3], ...
                          'PrecCoord'     , 3, ...
                          'ColumnWidth'   , 10);
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  philipp.glira@gmail.com
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