To quantify land use changes within the study area, satellite images (Landsat) with minimal cloud cover from Landsat 8/9, Landsat 7, and Landsat 5 satellites were utilized from the Landsat Collection 2 – Level 1 dataset. Radiometric corrections were performed to rectify existing errors and atmospheric distortions using ENVI, GIS, and Google Earth software. Initially, land uses were classified into 4 and 5 classes for the years 1993, 2003, 2013, and 2023. The accuracy of classification was calculated, and the area of each land use type for each year was determined.
Subsequently, in Google Earth software, samples were selected for all images separately, and classification methods such as Maximum Likelihood, Minimum Distance, Neural Network, and Support Vector Machine were employed to obtain the best Kappa coefficient. This process allowed for the identification of the most accurate method with the highest Kappa coefficient for determining changes that occurred over three decades, delineated in ten-year intervals. This analysis aimed to reveal which land use types converted to others and the corresponding areas during each decade.
Classification: In this paper, to determine land uses in the years 2023 and 2013, four land use classes were used: Urban (man-made), Gardens (forest), Agricultural lands (plowed) and Barren lands (mountains, etc.)
Additionally, for the years 2003 and 1993, five classes were utilized, including the aforementioned four classes plus a class for water bodies. For the classification of images in the four time periods, a supervised classification method was employed. For each class, 70 samples were used, totaling 280 samples for the 2023 and 2013 maps and 350 samples for the 2003 and 1993 images.
Class Separability
The accuracy of separating the selected classes depends on the accuracy, number, and size of the samples. To compare classes and selected samples, the Compute ROI separability command is used, which yields results in a table or matrix around the number 2. If the values are closer to 2, it indicates a higher possibility of separating classes from each other with greater ease. However, as the distance from the number 2 increases, the homogeneity of the area decreases, making it harder to discern phenomena or classes, and the likelihood of errors increases.
The fundamental point in producing land use maps lies in the precision of determining the training samples (first sample) and, importantly, the validation sample (essentially based on a thorough understanding of the region through either physical survey or software such as Google Earth). Furthermore, increasing the number of selected pixels for each category in each sample will enhance the accuracy of the generated raster map. This is reflected in the ROI Separability report, where in this study, the minimum separability value is 1.94150149 for the barren lands with agriculture in 1993, 1.995442302 for gardens with agriculture in 2003, 1.98556922 for agricultural lands with barren lands in 2013, and 1.99945853 for gardens with urban lands in 2023.
Validation using Kappa Coefficient
The Kappa coefficient measures accuracy inversely to the overall accuracy based on all pixels that are correctly and incorrectly classified. In the current paper, Kappa coefficients above 79% along with appropriate accuracy of classified images will yield acceptable results. Following the classification, classes are supervised and necessary sampling is done using Google Earth software, which requires precise knowledge of the study area. Sampling for each image is done separately; for each class in ENVI, 70 samples are taken, and for images of 2023 and 2013 in Google Earth Pro, 50 samples per class are taken, totaling 200 samples for each image. For images of 2003 and 1993, considering they have five classes, 250 samples are selected, totaling 900 samples for all four images and all classes. Specifically, 400 samples are for images of 2013 and 2023, and 500 samples are for images of 1993 and 2003 in Google Earth. In total, approximately 1260 selected samples are drawn. The results, including the concordance of these samples in terms of error percentage and Kappa coefficient for each year using the introduced methods, are presented in the following tables
Table 1
Results of error matrix and Kappa coefficient in 1993
| Overall accuracy | Number of errors | kappa |
Maximum likelihood | 85.42% | 164/192 | 0.8114 |
Minimum-distance | 71.3542 | 137/192 | 0.6303 |
Neural network | 80.2083 | 154/192 | 0.7402 |
Support vector machine | 80.2083 | 154/192 | 0.7429 |
Based on the Kappa coefficients obtained, the best classification method for the year 1993 (Table 1) is the Maximum Likelihood method, with a Kappa value of 0.81 and an accuracy of 85%. Out of 192 selected samples, 164 samples were accurately classified while 28 samples were misclassified. Among these, 56 samples were urban areas, 47 samples were agricultural land use, 31 samples were barren land, 45 samples were gardens, and 13 samples were water bodies. The highest error occurs between the barren land and agricultural land use classes, while the lowest error is observed in the urban land use class, with an accuracy of 93%.
Table 2
Results of error matrix and Kappa coefficient in 2003
| Overall accuracy | Number of errors | kappa |
Maximum likelihood | 75.3676 | 205/272 | 0.6782 |
Minimum-distance | 59.5588 | 162/727 | 0.4837 |
Neural network | 69.8529 | 190/272 | 0.6075 |
Support vector machine | 67.6471 | 184/272 | 0.5855 |
For the land use classification of the year 2003, 272 samples were selected. The Maximum Likelihood method exhibits the least error, with a Kappa coefficient of 0.67 and an accuracy of 75% (Table 2). Out of these samples, 205 samples were consistent with the Google Earth imagery. Specifically, 64 samples were urban areas, 86 samples were agricultural land, 40 samples were barren land, 73 samples were gardens, and 9 samples were water bodies. Gardens achieved the highest accuracy at 99%, followed by agricultural land at 79%, urban areas at 78%, barren land and water bodies at 48% and 42% accuracy respectively. However, in terms of error, it's notable that barren land and water bodies exhibit relatively higher inaccuracies, which could potentially result in significant inaccuracies in area estimation.
Table 3
Results of error matrix and Kappa coefficient in 2013
| Overall accuracy | Number of errors | kappa |
Maximum likelihood | 79.4425 | 228/287 | 0.7247 |
Minimum-distance | 76.3066 | 219/287 | 0.685 |
Neural network | 90.2439 | 259/287 | 0.8699 |
Support vector machine | 89.547 | 257/287 | 0.86.6 |
Considering the classifications conducted using the four methods, the neural network emerges as the best approach with an accuracy of 90.24% for the image of the year 2013 (Table 3). The error rate for the four classes is 10%, which is acceptable, resulting in a Kappa coefficient of 0.8625. This coefficient is deemed acceptable for validation and matching the selected classes with reality. According to the Kappa coefficient table, out of the 28 errors observed, 7 errors occurred between urban areas and agricultural land, barren land, and gardens; 8 errors occurred from agricultural land to urban areas, barren land, and gardens; 9 errors occurred from barren land to agricultural land and gardens, and 4 errors occurred from gardens to both barren land and agricultural land classes. Urban areas had a 91% accuracy rate, agricultural land had an 89% accuracy rate, barren land had an 88% accuracy rate, and gardens had a 95% accuracy rate.
Table 4
Results of error matrix and Kappa coefficient in 2023
| Overall accuracy | Number of errors | kappa |
Maximum likelihood | 79.4425 | 228/287 | 0.7247 |
Minimum-distance | 84.4203 | 233/276 | 0.792 |
Neural network | 92.029 | 254/276 | 0.8932 |
Support vector machine | 92.3913 | 255/276 | 0.8981 |
Among the employed methods, the neural network appears to be the most suitable approach for the image of the year 2023, achieving the highest possible accuracy (Table 4). Out of 276 selected samples, 254 were correctly classified, while 22 samples contributed to errors across all classes. The overall measurement accuracy for this image was 92%, with a corresponding Kappa coefficient of 0.89.
In this image, urban areas had a 90% correct selection rate, agricultural land had a 64% correct selection rate, barren land had an 88% correct selection rate, and gardens had a 97% completely correct selection rate. The distribution of errors in terms of percentages is as follows: the highest error rate, at 2.63%, occurred between agricultural land and urban areas and gardens. Barren land had a 12% error rate with agricultural land, gardens had a 3% error rate with agricultural land, and urban areas had the highest error rate of 8% with barren land.
4.1. Image Classification
Classification of the 1993 Image
For the image of the year 1993 with 5 land use classes, considering the changes and classifications conducted, the Maximum Likelihood method, with the highest Kappa coefficient of 0.81, is the most suitable method for classifying this image (Fig. 2).
Table 5
classified map data in 1993
Name | Count | Area | Percent |
Urban | 4427 | 4630.63 | 17.30 |
Agriculture | 4062 | 6448.03 | 24.1 |
Water | 805 | 227.26 | 0.85 |
Barren | 6050 | 5210.61 | 19.47 |
Gardens | 1296 | 10252.15 | 38.3 |
Total | 16440 | 26768.7 | 100.0 |
Based on the data provided in the table, the areas of the five land use classes - urban, agricultural, water, barren, and gardens - with pixels measuring 30*30 square centimeters, are respectively 4630.63, 6448.03, 227.26, 5210.61, and 10252.15 hectares out of a total area of 26768.7 hectares. These areas cover the specified region, with gardens covering the largest area at 38.3% and water covering the smallest area at 0.85%, which is linear and only represents the Silvana River. Agricultural land, barren land, and urban areas represent 17.30%, 19.47%, and 24.1% of the total land, respectively (Table 5).
Image Classification 2003
For the image of the year 2003 with 5 land use classes, the Maximum Likelihood method has been utilized. According to the map and its legend, urban areas are represented in red, gardens or forest-like areas in green, barren land in light blue, river water areas in light blue, and plowed agricultural land, with wheat and barley, in yellow (Fig. 3).
Table 6
classified map data in 2003
Name | Count | area | Percnt |
Urban | 4778 | 5569.77 | 20.81 |
Water | 509 | 89.21 | 0.33 |
Agriculture | 10861 | 7854.64 | 29.34 |
Barren | 7420 | 4254.98 | 15.90 |
Gardens | 8125 | 9000.08 | 33062 |
Total | 31693 | 26768.7 | 100.00 |
The satellite image of the year 2003 comprises 5 land use classes with a total area of 26768.7 hectares, with pixels measuring 15*15. Urban areas cover 5569.77 hectares, water areas cover 89.1 hectares, agricultural land covers 7854.64 hectares, barren land covers 4254.98 hectares, and gardens cover 9000.08 hectares. Barren land constitutes the largest area at 33.62%, while water areas constitute the smallest area at 0.33%. Gardens, agricultural land, and urban areas account for 20.81%, 29.34%, and 15.90% respectively. Compared to 1993, the changes in each class are as follows: a decrease of 0.57% in barren land, an increase of 5.25% in agricultural land, a decrease of 4.68% in gardens, a decrease of 0.52% in water areas, and an increase of 3.51% in urban or human-made areas (Table 6).
Image Classification 2013: For the image of the year 2013 with 4 land use classes, the best method is the neural network. The classes are well separated from each other, with the coloring as follows: urban areas are depicted in yellow, garden or forest-like areas in light green, barren land in gray, and plowed agricultural land, with wheat and barley, in light green (Fig. 4).
Table 7
classified map data in 2013
Name | Count | area | Percent |
Urban | 8999 | 5501.27 | 20.55 |
Agriculture | 19762 | 8585.91 | 32.07 |
Barren | 5270 | 6104.7 | 22.81 |
Gardens | 10453 | 6576.7 | 24.57 |
Total | 44484 | 26768.7 | 100 |
The changes in the year 2013 are as follows: initially, the reduction in the number of classes from 5 to 4 is due to the fact that after the completion of the Silvana Dam project, the Silvana River, which flows from Urmia city to Lake Urmia, partially opens its reservoirs solely for agricultural purposes. Consequently, the riverbed remains dry for most seasons and days of the year. Therefore, starting from 2013, we have removed the water class. Subsequent changes are as follows: urban areas increased by 20.55%, from 5569.7 hectares to 5501.57 hectares. Agricultural land, in terms of cultivation, experienced a 2.73% change, increasing from 7854 hectares to 8585 hectares. Barren land also increased by 6.9%, from 4254 hectares to 6104 hectares, and gardens decreased by 9.05%, from 9000 hectares in 2003 to 6576 hectares in 2013.
The satellite image of 2013, with pixels measuring 15*15 square centimeters, covers a total area of 26768.7 hectares. Agricultural land constitutes 32.07% of this area, gardens cover 24.57%, urban areas cover 20.55%, and barren land covers 22.81% (Table 7).
Image Classification 2023: Similar to the image of 2013, the image of the year 2023 also consists of 4 land use classes, and the best method employed is the neural network. The classes are well distinguished from each other, with the following color scheme based on the map and its legend: urban areas (urban 2003) are depicted in yellow, gardens or forest-like areas (gardens 2003) in light green, barren land in gray, and plowed agricultural land, with wheat and barley (agriculture), in light green (Fig. 5).
Table 8
classified map data in 2023
Name | Count | Area | percent |
Urban | 9832 | 7697.96 | 28.76 |
Agriculture | 19527 | 8652.81 | 32.32 |
Barren | 10533 | 5930.24 | 22.15 |
Gardens | 5118 | 4487.68 | 16.75 |
Total | 45010 | 26768.7 | 100 |
In 2023, relative to the year 2013, there have been notable changes in the four existing land classes over a span of 10 years. Urban lands have experienced an 8.21% increase in area, expanding from 5501 hectares to 7697 hectares. Agricultural lands have seen a negligible increase of 0.25%, maintaining a relatively stable figure over the decade. Barren lands have decreased by 0.65%, shrinking from 6104 hectares to 5930 hectares. Additionally, gardens have witnessed a significant decline of 7.80%, decreasing from 6567 hectares in 2013 to 4487 hectares in 2023. In 2023, out of the total area of 26768.7 hectares, agricultural lands cover 8652.81 hectares, gardens cover 4487.68 hectares, urban and human-made lands encompass 7697.96 hectares, and barren lands contribute 5930.24 hectares to this total. This distribution is observed within a grid of dimensions 15*15 square centimeters (Table 8).
The results obtained from the four periods of 1993, 2003, 2013, and 2023 are as follows:
Table 9
Land use area in 4 time periods (1993-2003-2013-2023)
Name | Urban | Agriculture | Barren | Gardens | Water |
1993 | 4630.63 | 6448.03 | 5210.61 | 10252.15 | 227.26 |
2003 | 5569.77 | 7854.64 | 4254.98 | 9000.08 | 89.21 |
2013 | 5501.27 | 8585.91 | 6104.7 | 6576.7 | - |
2023 | 7697.96 | 8652.81 | 5930.24 | 4487.68 | - |
Min 2023 − 1993 | 3067.33 | 2204.78 | 719.63 | 5764.47- | - |
According to the Fig. 6, over three decades from 1993 to 2023, the changes in land use within the studied area of 26768.7 hectares are as follows: riparian lands for the Silvana River, which were only flowing in 1993 and 2003 due to the completion of the Silvana dam construction, are now only used for agricultural purposes. Therefore, since 2003, water reservoirs are only opened in spring and summer months, and the riverbed also passes linearly through the city center, its width has decreased, and urban constructions and vegetation cover have been established around it. This classification was omitted in the 2013 and 2023 images.
Urban or human-made lands, which are among the most significant objectives of this study, have consistently shown an upward trend from 1993 to 2023, as indicated in the chart. There has been significant growth in such a way that during these three decades, an area of 3067 hectares has been added to it, approximately doubling its area compared to 1993, representing a 66% increase in area over these three decades. This expansion consistently leads to environmental degradation, destruction of natural lands, steppes, and gardens.
Agricultural lands, typically cultivated with wheat, barley, and chickpeas within the study area, have also undergone incremental changes. Due to the proximity to Urmia city and expansion beyond its boundaries, coupled with advancements in agricultural tools, more steps are being cultivated, and more natural lands are being destroyed. Specifically, these lands increased from 6448 hectares in 1993 to 8652 hectares in 2023, representing a 34% increase over the past three decades. Steppes increased from 5210 hectares in 1993 to 5930 hectares in 2023, partly due to methodological errors.
The most significant degradation and transformation occurred in the classification of gardens, which consistently showed a declining trend. Its area decreased from 10252 hectares in 1993 to 4487 hectares in 2023, marking a 56% reduction compared to the total area. It can be said that this area halved in 2023 compared to 1993. Most of the changes observed are related to the conversion of gardens to urban or human-made lands and agricultural lands (Table 9).
4.2. Investigating Changes
Using the Thematic Change Workflow, we derive land use changes from 1993 to 2023 by comparing images from different periods. Initially, we compare the images of 1993 with 2003, then the changes obtained from the 2003 images are compared with those from 2013, and finally, we compare the images of 2013 with 2023. Ultimately, to ascertain the land use changes over the past three decades within the study area, we utilize a comparison between the images of 1993 and 2023.
Changes from 1993 to 2003
In the examination of land use changes within the study area, according to the land use change map of 2003 compared to 1993, alterations have occurred in 35 different scenarios among the defined 5 land use change classes. However, in 7 instances of these classifications, where no changes have occurred, the least change is attributed to barren lands remaining as barren lands, amounting to 18 pixels with an area of 3.05 hectares. The most substantial land use transformation over the span of 10 years for barren lands amounts to 621.91 hectares, converted into agricultural lands. This transformation is primarily due to human activity, as barren lands surrounding and extending beyond the urban limits have been cultivated, leading to environmental degradation.
Agricultural lands have experienced minimal changes, with 9.17 hectares transitioning from agriculture to water bodies, and the most significant change being 775.8 hectares of agricultural lands remaining uncultivated and barren. It should be noted that due to seasonal fluctuations when crops are not cultivated, most agricultural lands are identified as barren during certain months of the year.
The least changes observed pertain to water bodies, particularly the Silvana River basin, where the least alteration along its course amounts to 11.19 hectares, converted into barren lands. This segment could be attributed to the depletion of water resources in this area, leading to the emergence of barren lands. The most significant transformation involves the conversion of these lands into urban areas, amounting to 92.64 hectares.
Subsequently, changes in gardens exhibit the least alteration, with 17.67 hectares transitioning into water bodies, while the most substantial change involves their conversion into gardens in the vicinity of Urmia city, totaling 832.36 hectares.
The most crucial changes pertinent to this study are those associated with urban and human-made lands. It is imperative to understand the predominant types of transformations occurring within urban areas and identify the predominant land use changes. The least urban land use change amounts to 9.2 hectares transitioning into water bodies, converted into riverbeds. Conversely, the most significant change amounts to 490 hectares transitioning into gardens. It can be inferred that urban areas have experienced more extensive development than expansion into surrounding areas over the ten-year period from 1993 to 2003 (Table 10, Fig. 7).
Furthermore, the most substantial urban degradation has occurred on the outskirts of the city, with changes from suburban to agricultural and gardens, indicating a population influx towards the city center, resulting in high population density. The largest area of land transformed into urban areas is attributed to the conversion of gardens in the northern and northeastern parts of Urmia, totaling 781.13 hectares. Conversely, the least transformation into urban areas amounts to 92.64 hectares, transitioning from water bodies to urban and human-made lands.
Table 10
Land use change from 1993 to 2003
Name | Urban | Agriculture | Barren | Gardens | Water |
Urban | 3635 | 353.87 | 140.93 | 490.91 | 9.2 |
Agriculture | 666.85 | 4401 | 775.8 | 557.2 | 9.17 |
Barren | 454.33 | 1671.07 | 2384.19 | 621.91 | 3.05 |
Gardens | 781.13 | 1268.47 | 832.36 | 7380.77 | 17.67 |
Water | 92.64 | 23.4 | 11.19 | 46.7 | 40.06 |
Changes from 2003 to 2013
The changes that occurred from 2003 to 2013, according to the table and land use change map, indicate that the least alterations in the water bodies class amount to 1.93 hectares, which have been converted into agricultural lands, while the most significant changes in this class amount to 46.09 hectares, transformed into barren lands in 2013.
In the agricultural land’s class of 2003, the least changes amount to 1125 hectares, converted into barren lands, while the most substantial alterations in this class amount to 522 hectares, transformed into gardens. This implies that more than 522 hectares of agricultural lands were destroyed and converted into gardens from 2003 to 2013 (Table 11).
The least changes in the barren lands class amount to 202.75 hectares, converted into urban areas, while the most significant alterations in this class over the ten-year period amount to 1621.58 hectares, transformed into agricultural lands. These changes predominantly occur in the northern and southwestern outskirts of Urmia city. The most minor changes in the gardens class amount to 523 hectares, converted into urban and human-made lands, while the most significant alterations in this class over the ten-year period occur in barren lands. However, this change is not in the form of gardens disappearing entirely; rather, it is due to the preservation of garden land use itself, but changes arise due to alterations in irrigation methods and the age of gardens.
The most significant changes occur in urban lands, with the least area of change being 8.946 hectares, converted from human-made lands into agricultural lands, while the most substantial alterations amount to 110.997 hectares, transformed into barren lands. Most of these changes manifest as access roads between urban areas and their surroundings. Furthermore, during this period from 2003 to 2013, the most significant changes in transitioning to urban lands amount to 1901745 hectares, converted into urban areas (Fig. 8).
Table 11
Land use change from 2003 to 2013
Name | Urban | Agriculture | Barren | Gardens | Water |
Urban | 3550.87 | 234.3 | 1695.28 | 185.43 | - |
Agriculture | 1376.82 | 4752 | 1125.53 | 522.56 | - |
Barren | 202.75 | 1621.58 | 1842.84 | 490.15 | - |
Gardens | 523.14 | 1693.95 | 1851.55 | 5017.21 | - |
Water | 1.93 | 14.46 | 46.09 | 19.52 | - |
Changes from 2013 to 2023
During the years 2013 to 2023 (Table 12), in the agricultural lands class, the least changes occurred, amounting to 313.16 hectares, which were converted into barren lands, while the most significant changes amounted to 1020.55 hectares, transformed into urban and human-made lands. In the gardens class, the least area of change was 80.49 hectares, converted into urban and human-made lands, while the most substantial change was 598 hectares, converted into agricultural lands.
In the urban lands class during this period, the least transformation occurred, with an area of 19.51 hectares converted into gardens, while the most significant change, with an area of 346 hectares, was converted into barren lands. Most of these alterations occurred in large areas outside the city, such as access roads and abandoned workshops, which were transformed into barren lands. Barren lands experienced the least conversion to urban areas, with an area of 905 hectares, while the most significant changes, amounting to 2959 hectares, were converted into agricultural lands (Fig. 9).
Over the course of these ten years, the least area converted to urban lands was 80 hectares, transformed from gardens into urban areas. The most significant changes to urban lands occurred in the outskirts and urban expansion areas, with an area of over 1020 hectares converted from agricultural lands into urban areas. In total, more than 200 hectares of garden, barren, and agricultural lands were transformed into urban areas over the ten-year period, indicating urban expansion within Urmia city.
Table 12
Land use change from 2013 to 2023
Name | Urban | Agriculture | Barren | Gardens | Water |
Urban | 5851.44 | 199.78 | 346.02 | 19.51 | - |
Agriculture | 1020.55 | 4067.72 | 313.16 | 377.76 | - |
Barren | 905.1 | 2959.96 | 4671.63 | 924.11 | - |
Gardens | 80.49 | 1127.11 | 598.32 | 3305.96 | - |
Water | - | - | - | - | - |
Changes from 1993 to 2023
Over the three decades from 1993 to 2023 (Table 13), the summary of changes for five land use classes between 1993 and 2003, and four land use classes between 2013 and 2023 is as follows
For urban lands, the least changes occurred, amounting to 233.33 hectares converted into gardens, while the most significant area transformed, totaling 1384 hectares, was converted into barren lands. In agricultural lands, the least changes observed were 165 hectares converted into gardens, whereas the most significant alteration amounted to 2518 hectares transformed into urban areas.
In the water class, measured only over two decades, the smallest conversion area was 20.65 hectares, transformed into urban lands, while the most substantial changes were 121.39 hectares converted, respectively, into urban and barren lands.
Throughout these 30 years, barren lands experienced the least changes, with 295.31 hectares converted into gardens, and the most significant alterations, with 2183 hectares converted into agricultural lands. Gardens had the least changes, with 1546 hectares converted into urban lands, and the most substantial changes, with 2887 hectares converted into gardens (Fig. 10).
The most considerable changes occurred in the urban and human-made land use class, with the least transition observed in water class, converting 20.65 hectares into urban lands, and the most significant change, with 2518 hectares converted from agricultural to urban lands. Moreover, over these three decades, the least change occurred from water to urban lands, with 20.65 hectares, and the most significant transformation was from gardens to agricultural lands, with 2887.41 hectares.
Table 13
Land use change from 1993 to 2023
Name | Urban | Agriculture | Barren | Gardens | Water |
Urban | 2691.8 | 316.34 | 1384.08 | 233.33 | - |
Agriculture | 2518.85 | 2973.33 | 763.82 | 165.79 | - |
Barren | 1059.81 | 2183 | 1622.62 | 295.31 | - |
Gardens | 1546.21 | 2887.41 | 1972.77 | 3834.4 | - |
Water | 20.65 | 34.93 | 121.39 | 43.67 | - |
4.3. Urban Areas
According to the results obtained from land use changes, urban areas do not deteriorate over time and are converted to other uses. Therefore, urban areas should increase compared to previous periods. To rectify this error, we utilized the ERASE tool in GIS software to minimize these errors on urban land parcels according to the maps (Fig. 11).
In 1993, the urban land area was 3953.95 hectares, which increased to 5179.74 hectares in 2003. By 2013, the urban or human-made land area had reached 5411.37 hectares, and finally, in 2023, it reached 7697.96 hectares. In the comprehensive plan of Urmia city in 2016, the urban area boundary was declared as 10,000 hectares. However, the results obtained indicate discrepancies due to processing errors, unclear delineation of the urban boundary, and the absence of a road network matching the declared boundary in the Urmia comprehensive plan.
4.4. Factors
To identify the factors influencing land use changes, various dimensions and reasons for urban growth and expansion at a global level were identified after research in various sources. In this regard, the Fuzzy Delphi method was used to achieve this goal. By collecting opinions from urban experts in Urmia, several steps were taken to identify the factors affecting land use changes in Urmia through defining the research problem, dimensions, and various components using factor analysis. The criteria introduced by the experts categorized these factors into 6 dimensions as follows (Table 14). In these 6 categories, the first three dimensions are particularly important and are the main drivers of changes, while the other three dimensions are supportive and complementary to the first three dimensions, hence not significantly impactful on land use changes.
Table 14
Criteria | Explanation |
Social Dimension (Population) | Rate, growth, and density of the population |
Living Standards | Economy, income levels, and livelihood of individuals |
Technological Advancement | Transportation, construction of power plants, industries, etc. |
Political Economy | Production and distribution of income and public wealth in various regions of Urmia |
Political Structure | Political system, role of the government, plans and policies, management |
Attitudes and Values | Culture, customs, and traditions of the city's ethnic groups and religions (Urmia) |
By selecting these 6 dimensions according to the experts' opinions, the main criteria for each dimension were determined. Then, through reviewing the literature of various research studies and investigations and considering the opinions and suggestions collected from 60 experts, 60 indices were introduced for each of these dimensions. To identify the effective factors, 25 components out of the mentioned 60 sub-criteria entered the analysis. The oblique rotation method was used for Factor analysis, determining the factors based on the assumptions of the test, with eigenvalues of 0.5 or 1. The aim was to identify the best model and eliminate inefficient variables with lower factor loads that had insignificant correlations with other variables. Meaningful factor loads with higher significance coefficients in each factor analysis round, exceeding 0.5, were selected for a more precise and better analysis. As a result, 6 factors were extracted, encompassing 19 variables. Variables related to land use changes were categorized into these 6 factors based on their eigenvalues.
Table 15
Eigenvalues, Percentage of Variance, and Cumulative Percentage
| Initial Eigenvalues | Sum of Squared Loadings | Sum of Squared Loadings After Rotation |
Total | Percentage of Variance | Cumulative Percentage | Total | Percentage of Variance | Cumulative Percentage | Total |
1 | 4.625 | 18.499 | 18.499 | 4.625 | 18.499 | 18.499 | 3.908 |
2 | 3.627 | 14.509 | 33.008 | 3.627 | 14.509 | 33.008 | 3.521 |
3 | 2.941 | 11.765 | 44.773 | 2.941 | 11.765 | 44.773 | 3.185 |
4 | 2.402 | 9.61 | 54.383 | 2.402 | 9.61 | 54.383 | 2.582 |
5 | 2.294 | 9.175 | 63.558 | 2.294 | 9.175 | 63.558 | 2.572 |
6 | 1.929 | 7.716 | 71.274 | 1.929 | 7.716 | 71.274 | 2.728 |
Table 15 represents the number of factors extracted from the data (initial variables). Factors in this section are considered influential if their characteristic value (sum column) is greater than one. The last column of this table indicates the percentage of variance explained by all factors (from the first factor to the current factor) together. According to the table, 6 factors have been extracted, which collectively account for 71.274% of the variability of the main variables. The total variance for each test is equal to 100%. The closer this value is to 100, the better the interpretation of the number of factors. The eigenvalue for the first factor is 4.625. Other eigenvalues for subsequent factors are also listed in the Total column.
The scree plot (Fig. 12) graphically displays the eigenvalues of each of the extracted components, starting from the largest eigenvalue. It consistently exhibits a descending slope. The scree plot indicates which factor had a noticeable change. It's quite evident that the initial 3 factors have a steeper slope compared to the second set of 3 factors. In fact, the results from the Total Variance Explained table are observed graphically in the scree plot, revealing which factor contributes to a higher percentage of variability in the variables. It's apparent in the plot that the initial 3 factors encompass more variability, covering 44% of the total, while the subsequent 3 factors also cover nearly 27% of the variability, as visible in the plot. Considering the scree plot, factors 7 and 8 could also be taken into account.