Hemisfer results
Results file
Hemisfer writes its results into plain-text files, a first one for
the LAI or single-tree leaf area, a
second one for the local analysis of the light regime.
Corresponding settings are available in the Options
dialogue, tab Results.
Hemisfer can work in a batch mode and users have
therefore the choice to have either all the results in the same file or to have
one file of results for each picture. In the first case, the name and location of
the results file can be chosen by the user. To do this, click on the
button. If the file already
exists, then new results will be appended to the existing ones. A comment line can
be entered which will be included into the results file.
If the option of one file for each picture is active, then the user can only choose
the extension of the results files. Their basename will be taken from the name of
corresponding pictures, and the files will be saved in the same folder as the
pictures. For example, if the extension is *.dat, then the results from
picture01.jpg will be saved in picture01.dat.
If the file name has the extension CSV, then the results will be written separated
by comma (CSV = comma-separated values). If it has the extension SSV, SKV or SCSV,
then the results will be written separated by semi-columns. TXT or PRN extensions
correspond to a preformatted format, using spaces to align columns. Otherwise,
the data will be written separated by tabulators. In all cases, it is easy to import
these formats into a text-editor, a spreadsheet, a statistical or a graphical
software. The current results file can be opened by clicking on the
leaf area or LAI results or on the
light regime results button on the
main window, or by selecting the corresponding options in
the File menu. Which software is used to open these files
depends on the file type (file extension) and on the corresponding settings on a
particular computer. In fact, the same should happen as if the icon of the file
would be double-clicked from your file explorer. CSV files, for example, are usually
set to be opened with your preferred spreadsheet software and TXT will normally by
opened in your plain-text editor. If this doesn't work, then Hemisfer tries to
open the file with Window's notepad. Three examples of results with comments are
available, one for the LAI results, one for the
single-tree results , and the last one for
light regime results. Look at them to understand what
the obtained numbers mean.
Level of detail (LAI)
Within the options for the results, the user can
chose the level of detail to which the LAI results are stored. This option is
saved when exiting Hemisfer and retrieved the next time the software is
used.
| global results |
Only the leaf area index and the
leaf angle for the different
analysis methods are given, all on one single line
per picture. If the canopy clumping is calculated,
then the Ω-corrected values for the same picture come on another
line of results. Results from the slope and non-linearity
correction come on yet another line.
If chosen in the options, the gap fraction in vertical
projection (Fmv) is given for those methods allowing its calculation:
Norman & Campbell (1989) and
Thimonier et al., 2010. In conjunction with a
clumping correction method, the large gaps in
vertical projection (Fmr) are then also given. |
| detailed results |
Compared to the previous option, the number of white and black pixels, the
total light transmission, and the proportion of large gaps
(if calculated) are also included into the results for the sum of the
rings. |
| full results |
This option further gives the following results: picture size, site name,
lens name and coefficients,
gamma value as used to calculate the
threshold, weights of the
colour channels, number and width of
rings. If applicable, the
limits of mean leaf angles are also given.
The following values are also given per ring:
mean zenith angle, white and black pixels, light
transmission, contact points and, if calculated,
the proportion of large gaps and the
clumping index Ω. See an
example. |
| synthesis per site |
If several parameter files are loaded and analysed
as a batch, then they will be treated in alphabetical order. If the synthesis
option is set, then successive files with the same site name will be grouped
into a summary.
For the calculations after Walter & Torquebiau
(2000), the summary is an average of all the usable sectors of the single
pictures. For the Norman & Campbell (1989) method,
the summary values are calculated by averaging the light transmission per ring
over the different photographs, then recalculating the LAI
and leaf angle. All other methods use the contact
numbers (K) of the rings as averaged over the pictures (weighted by the
non-ignored solid angles if necessary). The synthesis is thus not just an average
of the single LAI estimates, but rather an overall analysis of several
photographs. |