Parameter files

Several parameters and options affect the way a hemispherical picture will be analysed. This information can be stored into a separate file. To this purpose, Hemisfer uses plain-text file with the extension INI. Picture files and corresponding parameter files must be in the same folder and typically have the same name but a different extension, e.g. PICT3B.JPG and PICT3B.INI. The user, however, can also decide to use different names for parameter files, for example to differentiate between parameter sets using the same picture. INI files are saved with all the defined parameters. When a file is loaded again, however, the parameters marked as fixed in the options dialogue will be left unchanged, regardless of the value in the INI file. The same happens if a parameter is missing in the INI file because it has been manually deleted.

Because INI files are plain-text, it is easy to read and understand them. It is also possible to modify them directly with any plain-text editor. An INI file is organised in paragraphs with titles between square brackets (but these titles are only for clarity, they are actually skipped during file loading):

• [Image]
  • Filename= the name of the picture file (without its path); this is the only required parameter (all the others are optional)
  • Date= the date of the picture, in free text format; when no date is specified here as parameter, the date of the picture file is used (including time).
• [Colours]
  • Threshold= the largest brightness to be classified as black = canopy (higher brightness values are classified as white = sky) [0 - 254]
  • WeightRed= weighting of the red colour channel in % [-100 - +100]
  • WeightGreen= weighting of the green colour channel in % [-100 - +100]
  • WeightBlue= weighting of the blue colour channel in % [-100 - +100]
  • Gamma= the γ (gamma) value of the picture
  • IgnoreRed= red component of the colour to be ignored (if any) [0 - 255]
  • IgnoreGreen= green component of the colour to be ignored (if any) [0 - 255]
  • IgnoreBlue= blue component of the colour to be ignored (if any) [0 - 255]
  • Tolerance= tolerance to ignore a colour (because of non-conservative image compression) [0 - 127]
• [Position]
  • CenterX= X coordinate (from left to right) of the zenith on the picture
  • CenterY= Y coordinate (from top to bottom) of the zenith on the picture
  • Radius= radius of the circle representing the horizon (or the circle of visibility if the maximum zenith angle is less than 90°)
  • North= position (in degrees) of the magnetic north on the picture, clockwise from the top [0-359]
  • Declination= declination (in degrees) of the magnetic pole, positive if it is right of the geographic pole, negative if left [-90-+90]
• [Slope]
  • Slope= slope of the ground (in degrees)
  • Aspect= downhill direction (in degrees) relative to the geographic north, in clockwise direction on a map = in counter-clockwise direction on the picture [0-359]
• [Lens]
  • Lensname= name of the lens, which has to refer to a lens in the LENSES.CSV file
• [Site]
  • Sitename= name of the site, which has to refer to a site in the SITES.CSV file

Parameters from previous versions

These parameters are interpreted by the present version but no longer saved as such. They are converted into WeightRed, WeightGreen and WeightBlue since this new scheme offers more possibilities for fine tuning.

• AnalyseRed= 1 if the red colour component is analysed, 0 if it is omitted
• AnalyseGreen= 1 if the green colour component is analysed, 0 if it is omitted
• AnalyseBlue= 1 if the blue colour component is analysed, 0 if it is omitted

• Negative= 1 if the picture is negative, 0 if it is positive

Parameters from other software

Hemisfer is also able to read HVS parameter files generated by HemiView, a software by Delta-T. Parameters not defined in an HVS file (e.g. the slope) will be left unchanged.