Accounting (GWB_ACC)#

This module conducts the Accounting analysis. Accounting will label and calculate the area of all foreground objects. The result are spatially explicit maps and tabular summary statistics. Details on the methodology and input/output options can be found in the Accounting product sheet.

Requirements#

A single band (Geo)TIFF image in data format byte:

  • 0 byte: missing (optional)

  • 1 byte: background

  • 2 byte: foreground (forest)

  • 3 byte: special background 1 (optional)

  • 4 byte: special background 2 (optional)

Processing parameter options are stored in the file input/acc-parameters.txt.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; GWB_ACCOUNTING parameter file:
;; NOTE: do NOT delete or add any lines in this parameter file!
;;
;; ACC: Accounting of image objects and patch area size classes
;; Input image requirements: 1b-background, 2b-foreground, optional: 0b-missing
;; optional: 3b-special background 1, 4b-special background 2
;; Please specify entries at lines 25-29 ONLY using the following options:
;;
;; line 25: Foreground connectivity: 8 (default) or 4
;; line 26: spatial pixel resolution in meters:
;; line 27: up to 5 area thresholds [unit: pixels] in increasing order
;;          and separated by a single space.
;; line 28: output option:   default (stats + image of viewport) OR
;;   detailed (stats + images of ID, area, viewport; requires much more CPU/RAM!)
;; line 29: big3pink: 0 (no - default) or 1 (show 3 largest objects in pink color)
;;
;; an example parameter file with default output would look like this:
;; 8
;; 25
;; 200 2000 20000 100000 200000
;; default
;; 0
****************************************************************************
8
25
200 2000 20000 100000 200000
default
0
****************************************************************************

Example#

The results are stored in the directory output, one directory for each input image accompanied by a log-file providing details on computation time and processing success of each input image.

GWB_ACC Command and listing of results in the directory output:

$ GWB_ACC -i=$HOME/input -o=$HOME/output
IDL 9.1.0 (linux x86_64 m64).
(c) 2024, NV5 Geospatial Solutions, Inc.

GWB_ACC using:
dir_input= $HOME/input
dir_output= $HOME/output
% Loaded DLM: TIFF.
Done with: clc3class.tif
Done with: example.tif
Done with: gscinput.tif
Accounting finished sucessfully

$ ls -R output/
output/:
acc.log  clc3class_acc/  example_acc/

output/clc3class_acc:
clc3class_acc.csv  clc3class_acc.tif  clc3class_acc.txt

output/example_acc:
example_acc.csv  example_acc.tif  example_acc.txt

example statistics and graphical result of input image example.tif:

Accounting size classes result using:
example
Base settings: 8-connectivity, pixel resolution: 25 [m]
Conversion factor: pixel_to_hectare: 0.0625000, pixel_to_acres: 0.154441
----------------------------------------------------------------------------
Size class 1: [1, 200] pixels; color: black
        # Objects      Area[pixels]     % of all objects  % of total FGarea
            2789             31190           97.8596         7.2790497
----------------------------------------------------------------------------
Size class 2: [201, 2000] pixels; color: red
        # Objects      Area[pixels]     % of all objects  % of total FGarea
                44             23643           1.54386         5.5177484
----------------------------------------------------------------------------
Size class 3: [2001, 20000] pixels; color: yellow
        # Objects      Area[pixels]     % of all objects  % of total FGarea
                14             98972          0.491228         23.097855
----------------------------------------------------------------------------
Size class 4: [20001, 100000] pixels; color: orange
        # Objects      Area[pixels]     % of all objects  % of total FGarea
                2             59874         0.0701754         13.973255
----------------------------------------------------------------------------
Size class 5: [100001, 200000] pixels; color: brown
        # Objects      Area[pixels]     % of all objects  % of total FGarea
                0                 0           0.00000         0.0000000
----------------------------------------------------------------------------
Size class 6: [200001 -> ] pixels; color: green
        # Objects      Area[pixels]     % of all objects  % of total FGarea
                1            214811         0.0350877         50.132092
----------------------------------------------------------------------------
----------------------------------------------------------------------------
Sum of all classes:
        # Objects      Area[pixels]     % of all objects  % of total FGarea
            2850            428490           100.000         100.00000

Median Patch Size:                5
Average Patch Size:          150.347
Standard Deviation:          4143.11

Largest object:     214811
../_images/example_acc.tif

Accounting has been used to map and summarize forest patch size classes in the FAO SOFO2020 report and the Forest Europe State of Europe’s Forest 2020 report with additional technical details in the respective JRC Technical Reports for FAO and FE.