Connectivity Change (GWB_FOSCHANGE)#
This module conducts a temporal change analysis of a GTB/GWB FOS fragmentation/connectivity. The result consists of a spatially explicit change map, a change histogram, and tabular summary statistics. Details on the methodology and input/output options can be found in the section FOS change analysis of the Fragmentation product sheet.
Requirements#
We assume to have two GeoTIFF input maps of time A and time B. To be comparable, both maps must have a fully matching geoheader information: the same map extent, pixel resolution, (equal-area) projection, position, and map dimension in x/y.
Place the two matching input maps in the directory
inputand run a FOS-analysis including statistics via theGWB_FRAGmodule.Empty the directory
input.Move the resulting two GTB/GWB-generated FOS-directories from the directory
outputinto the directoryinputand empty the directoryoutput.Specify the full path to the two GTB/GWB-generated FOS-tif maps in the file
input/foschange-parameters.txt.Run the GWB_FOSCHANGE module
Note
The GWB_FOSCHANGE module will exit with an error if the two FOS-directories are not GTB/GWB-generated or have incompatible GeoTIFF FOS maps.
Example of processing parameters in the file input/foschange-parameters.txt.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; GWB_FOSCHANGE parameter file:
;; NOTE: do NOT delete or add any lines in this parameter file!
;; Change analysis of GTB/GWB-generated FOS-analysis
;; for example results of GWB_FRAG using FAD/FED/FAC_5/6 only, no FAD-APP/FED-APP!
;;
;; The result of GWB_FOSCHANGE (FOSchange.tif/csv/png, FOSchange_hist/colors.csv) are written into
;; the default output directory in standalone mode or the user-specified directory
;;
;; Requires two unmodified GTB/GWB-generated FOS-analysis directories of a FAD/FED/FAC_5/6 FOS analysis
;; The input directory must have the following GTB/GWB-generated files:
;; 1) the <FAD/FED/FAC>.png (histogram graph)
;; 2) the <FAD/FED/FAC>.sav (IDL-formatted summary statistics, mandatory)
;; 3) the <FAD/FED/FAC>.tif (GeoTIFF map of fragmentation/connectivity, mandatory)
;; 4) the <FAD/FED/FAC>.csv (fragmentation/connectivity summary spreadsheet)
;; 5) the <FAD/FED/FAC>.txt (fragmentation/connectivity summary plain text file)
;;
;; Please specify entries at lines 26-27 ONLY using the following syntax:
;; line 26: full path to the GTB/GWB-generated Fragmentation/Connectivity GeoTIFF map at time 1
;; line 27: full path to the GTB/GWB-generated Fragmentation/Connectivity GeoTIFF map at time 2
;;
;; example parameter file: specify the full path to the two FOS GeoTIFFS:
;; $HOME/input/FOS1/fm1990_fos-fad_5class_31.tif
;; $HOME/input/FOS2/fm2018_fos-fad_5class_31.tif
****************************************************************************
$HOME/input/PTfm1990_frag/PTfm1990_fos-fad_5class_31.tif
$HOME/input/PTfm2018_frag/PTfm2018_fos-fad_5class_31.tif
****************************************************************************
Example#
The resulting five files (FOSchange.tif/csv/png and FOSchange_hist/colors.csv) are stored in the directory output
together with a log-file providing details on computation time, peak RAM usage and processing.
GWB_FOSCHANGE command and listing of results in the directory output:
$ GWB_FOSCHANGE -i=$HOME/input -o=$HOME/output
IDL 9.2.0 (linux x86_64 m64).
(c) 2025, NV5 Geospatial Solutions, Inc.
GWB_FOSCHANGE using:
dir_input= $HOME/input
dir_output= $HOME/output
% Loaded DLM: TIFF.
% Loaded DLM: LAPACK.
% Loaded DLM: PNG.
FOSchange finished sucessfully
$ ls -R output/
output/:
FOSchange.csv FOSchange_hist.csv FOSchange_hist.csv foschange.log
FOSchange.png FOSchange.tif
Example statistics and spatial result of a FOSCHANGE analysis of two GWB_FRAG analysis using the fos-fad_5class reporting scheme.
1. The connectivity change map (FOSchange.tif): shows areas of insignificant change (light gray),
three degrees of connectivity decrease (yellow, orange, red) and increase (green tones),
water at either time (blue), and Foreground gain (bright green) and loss (black):
2. The connectivity change histogram summary (FOSchange.png): shows the proportion
of connectivity change for and normalised to the the area that is Foreground at both times.
Connectivity change is color-coded into seven classes: insignificant change [-1, 1]%, three
classes of connectivity decrease ([-100, -21], [-20, -11], [-10, -2]%) and three classes of
connectivity increase ([2, 10], [11, 20], [21, 100]%).
3. The connectivity change matrix summary file ( FOSchange.csv): shows summary
statistics of processing options and status and trend summaries for the two FOS maps.
1) General info:
Change typ: fos-fad_5class_31: change from A -> B
A: /home/user/input/PTfm1990_frag/PTfm1990_fos-fad_5class_31.tif
B: /home/user/input/PTfm2018_frag/PTfm2018_fos-fad_5class_31.tif
Pixel resolution [m]: 100.000
Window size: 31x31
Observation scale: 961.000 hectares ~ 2374.68 acres
Map area [pixels]: 20475000
2) Land cover status of A and B
Land cover Pixel value A-Pixels B-Pixels A-% B-% Net change-Pixels
Foreground [0 - 100] 3544408 2560104 17.3 12.5 -984304
Background [101 105 106] 12705784 13690474 62.1 66.9 984690
Missing [102] 4224808 4224422 20.6 20.6 -386
3) Land cover change matrix
A->B [pixels] B-Foreground B-Background B-Missing
A-Foreground 1828450 1715957 1
A-Background 731654 11973123 1007
A-Missing 0 1394 4223414
AREACOM 16249184
FORCOM 1828450
FG gain: 731654
FG loss: 1715957
4) FAD status: 5 classes
FAD FG cover Connectivity Fragmentation A-pixels B-pixels A-% B-%
[0 9] Rare Very low Very high 52689 93472 1.5 3.7
[10 39] Patchy Low High 983029 100971 27.7 39.4
[40 59] Transitional Intermediate Intermediate 1005188 765003 28.4 29.9
[60 89] Dominant High Low 1248124 639475 35.2 25.0
[90 100] Interior Very high Very low 255378 52439 7.2 2.0
Average Connectivity A B Absolute difference Relative difference
AVCON [%] 11.9 7.1 -4.8 -40.2
FAD_AV [%] 54.4 45.0 -9.4 -17.2
5) FAD change histogram: 7 classes, degree in DeltaFAD (= FAD change)
DeltaFAD Connectivity Color Pixels %
[-100 -21] High decrease RED 350027 19.1
[-20 -11] Medium decrease ORANGE 337221 18.4
[-10 -2] Low decrease YELLOW 496801 27.2
[-1 +1] Insignificant GRAY 209545 11.5
[+2 +10] Low increase LIGHT GREEN 271212 14.8
[+11 +20] Medium increase MEDIUM GREEN 104873 5.7
[+21 +100] High increase DARK GREEN 58771 3.2
Note: Change histogram is constrained to FORCOM [pixels]: 1828450
6a) AREACOM FAD change matrix: 5 classes listing FAD status change from A->B
A->B [pixels] B0-Background B1-Rare B2-Patchy B3-Transitional B4-Dominant B5-Interior
A0-Background 11973123 45905 361493 198439 117982 7835
A1-Rare 29774 12995 8857 842 204 17
A2-Patchy 531054 27374 339199 69917 14892 593
A3-Transitional 474238 3932 198227 262461 65433 897
A4-Dominant 563007 2768 91482 212239 365189 13438
A5-Interior 117884 498 10457 21105 75775 29659
AREACOM [pixels]: 16249184
Same classes: 12982626
Different classes: 3266558
Above matrix diagonal: 906744
Below matrix diagonal: 2359814
6b) FORCOM FAD change matrix:
A->B [pixels] B1-Rare B2-Patchy B3-Transitional B4-Dominant B5-Interior
A1-Rare 12995 8857 842 204 17
A2-Patchy 27374 339199 69917 14892 593
A3-Transitional 3932 198227 262461 65433 897
A4-Dominant 2768 91482 212239 365189 13438
A5-Interior 498 10457 21105 75775 29659
FORCOM [pixels]: 1828450
Same classes: 1009503
Different classes: 818947
Connectivity increase (=fragmentation decrease) - above the matrix diagonal [pixels]: 175090
Connectivity decrease (=fragmentation increase) - below the matrix diagonal [pixels]: 643857
6c) FORCOM FAD change matrix normalized by the 818947 pixels in different FAD status classes [%]:
A->B [%] B1-Rare B2-Patchy B3-Transitional B4-Dominant B5-Interior
A1-Rare 0.0 1.1 0.1 0.0 0.0
A2-Patchy 3.3 0.0 8.5 1.8 0.1
A3-Transitional 0.5 24.2 0.0 8.0 0.1
A4-Dominant 0.3 11.2 25.9 0.0 1.6
A5-Interior 0.1 1.3 2.6 9.3 0.0
Connectivity increase (=fragmentation decrease) - above the matrix diagonal [%]: 21.4
Connectivity decrease (=fragmentation increase) - below the matrix diagonal [%]: 78.6
4. The connectivity change histogram summary file ( FOSchange_hist.csv): shows a
tabular summary of the full range of the change histogram [-100, 100]%: the histogram index
and the corresponding pixel value in the map, connectivity change value, occurence frequency,
connectivity change class, color, and RGB color code.
Histogram Pixel-Value Delta-FAD FREQUENCY Connectivity-Class Color RGB
0 200 -100 0 High decrease RED 205/75/0
1 199 -99 0 High decrease RED 205/75/0
2 198 -98 0 High decrease RED 205/75/0
3 197 -97 0 High decrease RED 205/75/0
4 196 -96 12 High decrease RED 205/75/0
5 195 -95 32 High decrease RED 205/75/0
... ... ... ... ... ... ...
98 102 -2 62213 Low decrease YELLOW 255/215/100
99 101 -1 66876 Insignificant LIGHTGRAY 240/240/220
100 100 0 86441 Insignificant LIGHTGRAY 240/240/220
101 99 1 56228 Insignificant LIGHTGRAY 240/240/220
102 98 2 46670 Low increase LIGHTGREEN 130/210/170
... ... ... ... ... ... ...
191 9 91 5 High increase DARKGREEN 60/130/90
192 8 92 2 High increase DARKGREEN 60/130/90
193 7 93 0 High increase DARKGREEN 60/130/90
... ... ... ... ... ... ...
200 0 100 0 High increase DARKGREEN 60/130/90
5. The map pixel values file ( FOSchange_colors.csv): shows a
tabular summary of the unique pixel values found in the connectivity change map: the pixel
value in the map, connectivity change value, description, color, and RGB color code.
Pixel-Value Delta-FAD Description Color RGB
8 92 High increase DARKGREEN 60/130/90
9 91 High increase DARKGREEN 60/130/90
10 90 High increase DARKGREEN 60/130/90
11 89 High increase DARKGREEN 60/130/90
... ... ... ... ...
195 -95 High decrease RED 205/75/0
196 -96 High decrease RED 205/75/0
250 Foreground gain BRIGHTGREEN 0/255/0
251 Foreground loss BLACK 0/0/0
252 Background stable GRAY 225/225/225
253 Water BLUE 0/99/254
254 Missing WHITE 255/255/255
Remarks#
This module allows to conduct a connectivity change analysis of either FAD/FED/FAC, but not for Average-Per-Patch reporting, for which a change analysis is not meaningful.
More details are available in the section FOS change analysis of the Fragmentation product sheet.