Results from the classification of the satellite images in 2003, 2013, and 2023 are presented in the following figure. We classified 5 land use class types as Forest, Water, Cultivated land, Settlement, and Barren land. Areas of land under different land use categories as derived from the classification results are also given in Table.
Land Use and Land Cover Classes for 2003
The result of 2003 image showed that Crop land and Forest dominated the landscape of the Dhanusha District. The Cropland was found to be confined at the lower elevations with (82,318ha) 69.3% of total land area and a majority of Forest land was situated at a higher elevation around the Chure region with an area (27,799ha) 23.4%. The Barren land was present with (3,807ha) 3.2% of the total area. And water includes the area with (3,199 ha) 2.7%. The settlement areas were found to be comparatively less than that of forest and cropland represented by (1679ha) 1.4%. The distribution patterns of different LULC classes throughout the district are seen as in the (Fig. 4) below:
Land Use and Land Cover Classes for 2013
In 2013, the land cover distribution exhibited a significant predominance of cultivated land, which occupied 80,936.5 hectares, accounting for 68.13% of the total area. Forested areas were the second largest land cover type, encompassing 27,625.8 hectares, which equated to 23.25% of the total area. There was only a slight change in water bodies and barren land over the decade. Water bodies were spread across 2,896.2 hectares, making up 2.44% of the area which, while barren land covered 4,507.68 hectares, constituting 3.79%. Built-up areas expanded significantly over the decade. By 2013, this had increased to 2,836.5 hectares, representing 2.39% of the total area. This growth of 1,831.1 hectares (1.54%) reflects increased urbanization and infrastructure development.
Land Use and Land Cover Classes for 2023
In 2023, the land use land cover (LULC) analysis continued to show dynamic changes in the landscape. The area under cultivated land further decreased to 75,642.8 hectares, constituting 63.68% of the total area compared to 2003 and 2013 statistics. The Settlement area increased to (4,510.53ha) 3.80%. There is also a slight increase in Barren land with an area of (5451.48ha) 4.59%. The rest of the land use area (Forest, cultivated land, and Water) decreased. Although the area of forest and cultivated land decreased compared to the image of 2003 and 2013, forestland and cultivated land both were seen as dominating land use. The water decreased and had an area of (2,444.13ha) 2.06%. Cultivated land includes (79,071.33ha) 66.56% of the total area and forestland also decreased and had (27,324ha) 23% of the area.
Land Use and Land Cover Class Change between (2003–2023)
The result of the Land Use Land Cover Change Trend between 2003, 2013, and 2023 shows that all land use coverage decreased except for Settlement and Barren land. Cultivated land decreased from 82,318.05 ha in 2003 to 80,936.5 ha in 2013 and to 79,071.66 ha in 2023, indicating a reduction of 3246.39ha. Forest cover decreased from 27,799.2 ha in 2003 to 27,625.8 ha in 2013 and to 27,324.9 ha in 2023, reflecting a reduction of 474.3 ha. Built-up areas saw substantial growth from 1,679.31 ha in 2003 to 2,836.5 ha in 2013 and to 4,510.53 ha in 2023, reflecting an increase of 2831.22 ha. The water decreased by 0.64% i.e. 755.28ha within the given time frame whereas Barren land has seen to be increased from the year of 2003 and 2023 by 1.38% i.e. 1644.75ha.
Table 4
Composite table of area statistics (Hectare) of the Dhanusa district in 2003, 2013, and 2023 and their net change
LULC Classes | LULC 2003 | LULC 2013 | LULC 2023 | Area Change (2003–2013) | Area Change (2013–2023) |
---|
Area (Hectare) | Area (Hectare) | Area (Hectare) | Area (Hectare) | Area (Hectare) |
---|
Forest | 27799.2 | 27625.8 | 27324.9 | -173.4 | -300.9 |
Water | 3199.4 | 2896.2 | 2444.1 | -303.21 | -452.07 |
Barren land | 3806.7 | 4507.7 | 5451.5 | 700.95 | 943.8 |
Settlement | 1679.3 | 2836.5 | 4510.5 | 1157.19 | 1674.03 |
Cultivated land | 82318.1 | 80936.5 | 79071.7 | -1381.55 | -1864.84 |
Land Use and Land Cover Change Transition Matrix between 2003–2013 and 2013–2023
The LULC transition matrix for 2003–2013 and 2013–2023 depicted the transition from one class to another. In 2003–2013, the highest transition from barren land to cultivated land was 1736.2ha, followed by the conversion of forest to cultivated land by 1726.5ha, while in 2013–2023, the highest transition from forest to cultivated land (4737.6 ha) and the second highest transition from cultivated land to barren land by 3023.8ha occurred. There was also a large change of cultivated area to settlement during both transition years, with 1132.4ha and 3005ha in 2003–2013 and 2013–2023, respectively. It was mostly due to urbanization. Water and barren land occupy a small area in comparison to other land use classes. So, no significant conversion was seen between them. The area statistics of the transition map below show the transition from one land use to another.
Table 5
Statistical table of transition map from 2003–2013
LULC Classes | LULC 2013 |
Barren land | Settlement | Cultivated land | Forest | Water |
LULC 2003 | Barren land | 1761.83 | 48.25 | 1736.22 | 79.79 | 149.32 |
Settlement | 93.59 | 235.18 | 984.07 | 50.86 | 62.66 |
Cultivated land | 491.53 | 1132.44 | 77050.80 | 4072.85 | 228.53 |
Forest | 5.56 | 9.43 | 1726.45 | 26021.05 | 11.96 |
Water | 152.59 | 38.32 | 1934.75 | 224.91 | 450.66 |
Table 6
Statistical table of transition map from 2013–2023
LULC Classes | LULC 2023 |
Barren land | Settlement | Cultivated land | Forest | Water |
LULC 2013 | Barren land | 1499.89 | 11.03 | 883.88 | 22.45 | 87.68 |
Settlement | 65.16 | 1130.85 | 224.80 | 18.14 | 24.74 |
Cultivated Land | 3023.81 | 3005.02 | 73703.41 | 2020.46 | 1679.86 |
Forest | 313.91 | 46.19 | 4737.62 | 25248.74 | 102.22 |
Water | 169.21 | 26.61 | 278.97 | 26.35 | 402.60 |
Accuracy assessment
For the accuracy assessment, 100 of the sample points were taken for the validation. The overall accuracy obtained for the year 2003 is 82%, for the year 2013 is 87%, and for the year 2023 is 87%. The kappa value of the classified image of year 2003 obtained is 0.78, kappa value for 2013 is 0.81, and kappa value for 2023 is 0.84. Kappa values between 0.6 to 0.80 is substantial and 0.81 to 1 is almost perfect, our obtained kappa values are substantial for year 2000 and almost perfect for 2010 and 2020. Kappa values of < 0 reflect no agreement, 0–0.2 as slight, 0.2–0.41 as fair, 0.41–0.60 as moderate, 0.60–0.80 as substantial, and 0.81–1.0 as almost perfect agreement (Maingi et al. 2002; Manonmain and Suganya 2010). These estimates indicate that classification accuracies were of substantial and perfect agreement.
Table 7
Accuracy assessment of LULC map 2003
Classes | Forest | Water | Barren land | Settlement | Cultivated land | Total | User Accuracy (%) |
---|
Forest | 20 | 0 | 0 | 0 | 0 | 20 | 100 |
Water | 1 | 15 | 0 | 0 | 4 | 20 | 75 |
Barren land | 1 | 1 | 15 | 0 | 3 | 20 | 75 |
Settlement | 0 | 0 | 2 | 13 | 5 | 20 | 65 |
Cultivated land | 1 | 0 | 0 | 0 | 19 | 20 | 95 |
Total | 23 | 16 | 17 | 13 | 31 | 100 | |
Producer Accuracy (%) | 86.96 | 93.75 | 88.24 | 100.00 | 61.29 | Overall Accuracy 82% |
Kappa Coefficient: 0.775 |
Table 8
Accuracy assessment of LULC map 2013
Classes | Water | Barren land | Settlement | Forest | Cultivated land | Total | User Accuracy (%) |
---|
Water | 17 | 3 | 0 | 0 | 0 | 20 | 85 |
Barrenland | 0 | 18 | 0 | 0 | 2 | 20 | 90 |
Settlement | 0 | 2 | 17 | 1 | 0 | 20 | 85 |
Forest | 0 | 0 | 1 | 19 | 0 | 20 | 95 |
Cropland | 0 | 2 | 1 | 1 | 16 | 20 | 80 |
Total | 17 | 25 | 19 | 21 | 18 | 100 | |
Producer Accuracy (%) | 100 | 72 | 89.5 | 90.5 | 88.9 | Overall Accuracy: 87% |
Kappa Coefficient: 0.813 |
Table 9
Accuracy assessment of LULC map 2023
Classes | Forest | Settlement | Cultivated land | Barren land | Water | Total | User Accuracy (%) |
---|
Forest | 20 | 0 | 0 | 0 | 0 | 20 | 100 |
Settlement | 0 | 18 | 2 | 0 | 0 | 20 | 90 |
Cultivated land | 0 | 1 | 18 | 1 | 0 | 20 | 90 |
Barren land | 1 | 0 | 7 | 12 | 0 | 20 | 60 |
Water | 0 | 0 | 1 | 0 | 19 | 20 | 95 |
Total | 21 | 19 | 28 | 13 | 19 | 100 | |
Producer Accuracy (%) | 95.2 | 94.7 | 64.3 | 92.3 | 100.0 | Overall Accuracy 87% |
Kappa Coefficient: 0.838 |
Spatial Variables
The spatial variables selected for the current study are DEM, slope, distance to roads, and the distance to existing settlements. After relevant spatial variables (Fig. 3) were selected, geometry matching was conducted, which included the cell size of the raster data, NoData value, and coordinate reference system. The cell size, No Data value, and coordinate reference system are 30 m, 0, and WGS_1984_UTM_Zone_45 N, respectively, for all spatial variables.
In this study, Pearson’s correlation was used to measure the correlation between the variables which is one of the three correlation measurements that is available in the MOLUSCE plugin of QGIS.
Table 10
Evaluation of the correlation between variables using Pearson’s correlation method.
Spatial Variables | DEM | Slope | Distance to Road | Distance to settlements |
---|
DEM | - - | 0.5138 | 0.7453 | 0.5466 |
Slope | | - - | 0.3431 | 0.305 |
Distance to Road | | | - - | 0.4239 |
Distance to settlements | | | | - - |
LULC Change Transition Potential Modeling based on CA-ANN
The MOLUSCE approach was used to model transition potentials using an artificial neural network (ANN). The ANN employs a multilayer perception method with neighborhood (1 px), learning rate (0.1), maximum iteration (1000), hidden layer (10), momentum (0.05), fixed overall accuracy (-0.00341), minimum error for validation (0.03498), and validation kappa (0.965), as shown in Figure 10. The model employed 5000 randomly distributed samples to generate a spatial representation for the ANN.
The 2023 LULC was modeled using the initial and final rasters from the 2003 and 2013 LULC maps, respectively. The simulation model was constructed and evaluated against the real 2023 LULC. That yields a validation kappa of 0.965, an overall accuracy of 96.43%, and an overall kappa value of 0.927. (Fig. 11) depicts the real and simulated LULC maps for 2023, with their respective area coverages reported in (Table 11) and (Fig. 12) depicts the validation graph between actual and simulated LULC 2023.
Table 11
Actual and Simulated LULC of 2023
LULC Classes | Actual LULC | Simulated LULC | Area change (Ha) |
---|
Area (Ha) | Area (%) | Area (Ha) | Area (%) |
---|
Forest | 27324.90 ha | 23.00 | 26144.46 ha | 22.01 | -1180.44 ha |
Water | 2444.13 ha | 2.06 | 2465.55 ha | 2.08 | 21.42 ha |
Barren land | 5451.48 ha | 4.59 | 4898.79 ha | 4.12 | -552.69 ha |
Settlement | 4510.53 ha | 3.80 | 4423.86 ha | 3.72 | -86.67 ha |
Cultivated land | 79071.66 ha | 66.56 | 80870.04 ha | 68.07 | 1798.38 ha |
LULC Prediction
The LULC prediction for 2033 was carried out after receiving acceptable model validation results, with an overall kappa value of 0.927 being regarded as good accuracy by many researchers (Alam et. al., 2021; Aneesha Satya et. al., 2020; Perović et. al., 2018; Rahman et. al., 2017). Model validation combines the contents of two data sources while taking into consideration the features of actual and simulated LULC data (Lukas et. al., 2023). The LULC for 2033 was predicted using the LULC of 2013 and 2023 and the spatial variables were chosen for simulation. A kappa value of 0.75 was obtained. The predicted LULC map of 2033 along with its area can be seen in (Fig. 13) and (Table 12) respectively.
Table 12
Statistical table of Predicted LULC map of 2033
LULC Classes | Area (Ha) | Area (%) |
---|
Forest | 26941.54 | 22.67 |
Water | 719.24 | 0.60 |
Barren land | 3763.73 | 3.16 |
Settlement | 7227.63 | 6.08 |
Cultivated land | 80150.56 | 67.46 |