Research on Land Use Dynamic Change Based on RS Technique in The West Coast New Area of Qingdao

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Introduction 1.1 Research Background and Significance
As a new regional economic function area, the West Coast New Area of Qingdao is a representative in the new wave of opening up, reform and development.Its urban planning and land utilization changes are quite distinctive from those of traditional cities.The West Coast New Area of Qingdao is studied in this research in an attempt to investigate the characteristics and laws of land utilization changes from the perspective of temporal-spatial changes.All in all, the research findings will contribute to exploring the development planning of national new areas in the future [1], in addition to providing elementary data support for the study on national new areas.The study is conducted to provide scientific decision-making basis for land utilization and urban planning quickly and accurately.

Pre-treatment of Remote Sensing Image
After radiation calibration and atmospheric correction preprocessing of the three phase images, from the spectral curves of various land types, the spectral curves of the ground objects displayed on the remote sensing images after atmospheric correction become smooth, close to the spectral curve characteristics of the actual ground objects.As shown in Figure 1, 2 and 3 below, the image quality has been improved to a certain extent, laying a foundation for land use type classification.

Extraction of Information on Land Utilization Change
To begin with, interpretation marks of water area, agricultural and forestry land, and building land are determined.Samples of the type of ground objects can be directly determined through visual interpretation in the pre-treated remote sensing image.Then the classification of images is supervised using the likelihood method based on the training samples selected at an earlier stage.Meanwhile, the classified land utilization patches are treated upon classification, such as clustering and merging.Further, the supervised classification results can be evaluated in terms of accuracy using the confusion matrix, as shown in Table 1:

Data Statistics of Land Utilization Types
The areas of different land Utilization types in different years are obtained using ENVI5.3software, the classified statistical tool.And the area transfer matrix of land utilization types can be generated according to the area changes of different land utilization types, which presents the mutual conversion of various land utilization types in the study period.The transfer matrix of the land utilization area is shown in Table 2 and Table 3.The water area of the West Coast New Area of Qingdao was decreased by 27.5 square kilometers, with the area of building land increased by 75.42 square kilometers, and the area of agricultural and forestry land decreased by 47.9 square kilometers from 2013 to 2017.By comparison, the water area of the West Coast New Area of Qingdao was increased by 18.06 square kilometers, with the area of building land increased by 109.48 square kilometers, and the area of agricultural and forestry land decreased by 127.54 square kilometers from 2017 to 2021.The area of building land in the West Coast New Area of Qingdao was on the rise from 2013 to 2021, whereas the areas of agricultural and forestry lands were decreased due to the rapid economic development and accelerated urbanization process of the New Area.according to data analysis.As a result, large areas of other land types have been converted into building lands.But the area of water area is presented in a trend of first decreasing and then increasing, which was decreased by 27.5 square kilometers from 2013 to 2017, with a decline of 47% and recovered by 18.06 square kilometers from 2017 to 2021.

Analysis of Transferred Land Utilization Type
The transfer of different types and years is counted according to the classification results of land utilization types.Results are shown in Table 4 and Table 5: The largest conversion area is from agricultural and forestry land to building land from 2013 to 2017, reaching 136.0638 square kilometers, followed by the conversion from building land to agricultural and forestry lands, covering 77.9472 square kilometers, according to data analysis results of Table 4. Evidently, mutual conversion between agricultural and forestry land and building lands is a primary characteristic of land changes in the West Coast New Area of Qingdao from 2013 to 2017.The transferred amount from the water area to other area types is far greater than that from the water area to other area types, resulting in the declined area of water area.The largest conversion area is, equally, from agricultural and forestry land to building land from 2017 to 2021, reaching 181.143 square kilometers, followed by the conversion from building land to agricultural and forestry lands, covering 62.4411 square kilometers, according to data analysis results of Table 5.It can be seen that the land change of the West Coast New Area of Qingdao from 2017 to 2021 is also dominated by the mutual conversion between agricultural and forestry land and building land.

Summary and Analysis of Changes in Land
Utilization Type The overall change trend is the conversion of other land types such as agricultural and forestry land and water to building land, with an obvious change in the coastal and rural-urban integration areas.From the spatial perspective, there is a great change of land utilization in the central and southwestern areas.To be specific, an increase has occurred in the central building land due to the change of the development center of the West Coast New Area of Qingdao, leading to a gradual rise of building land area in the southwest in 8 years.And land utilization type is change slightly in the northern and eastern regions because of relatively stable land utilization structure with high development degree of lands such as the economic and technological development zone, bonded port area and Xuejiadao area in the east.

Analysis on the Driving Force of Land Utilization Change
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Conclusion
Land utilization types are classified in the study based on the phase III images of the West Coast New Area of Qingdao from 2013, 2017 and 2021 before analyzing the conversion between different land utilization types in different periods.The results show that agricultural and forestry land and water areas being conversed into building land is a major conversion structure of land utilization in the West Coast New Area of Qingdao at this stage.It is an inevitable cause of urban expansion.Serious challenges, however, pose severe challenges to local ecology along with the rapid development of the city.In such a context, undeveloped building lands should be checked in the subsequent development process to promote the efficiency of building land utilization.Moreover, ecological protection red line must be obeyed to protect cultivated land, thereby achieving the balance between economic development and ecological protection.

1. 2
Research Contents Research contents are presented below: (i) Extraction of land utilization classification data of the West Coast New Area of Qingdao in 2013, 2017, and 2021 are extracted.Images of the West Coast New Area of Qingdao in 2013, 2017 and 2021 were pre-treated via radiometric calibration, atmospheric correction, and image clipping.Based on this, land utilization types were divided for monitored classification with the maximum likelihood method through combining land utilization conditions and image characteristics of the West Coast New Area of Qingdao.(ii) Study on the characteristics of land utilization changes in the West Coast New Area of Qingdao.Land utilization transfer matrices from 2013 to 2017 and from 2017 to 2021 were obtained from the land utilization classification results of the West Coast New Area of Qingdao in 2013, 2017 and 2021.And the dynamic change laws, including the law of land type quantity, change speed, and mutual conversion between different types of land utilization in the West Coast New Area of Qingdao, were analyzed in accordance with the land utilization change information displayed in the transfer matrix.After that, the overall information and law of land utilization change in the West Coast New Area of Qingdao from 2013 to 2021 were obtained completely.(iii) Study on the driving force mechanism of land utilization change in the West Coast New Area.Some practical problems can be found in land utilization and urban construction in the West Coast New Area of Qingdao through analyzing the characteristics of land utilization change and driving factors behind the change from the perspectives of population mobility, policy

Fig. 1 Fig. 2 Fig. 3
Fig.1 Spectral reflectance of water area before and after atmospheric correction 3764% and 0.9765, respectively; the overall classification accuracy and the kappa coefficient in 2021 are 98.6642% and 0.9822, respectively.Apparently, the accuracy of the supervised classification results in 2013, 2017 and 2021 is in conformity with the accuracy requirements of land utilization classification.Results of land utilization classification in Phase III are obtained, as shown in Fig. 4, Fig. 5and Fig. 6:

2. Research on Land Utilization Classification 2.1 Acquisition of Remote Sensing Images Image
data utilized in this paper were acquired from geospatial data cloud, with LandSat8 OLI image data products with cloud amount not exceeding 5% selected.Images were acquired on Aug. 23th, 2013, Sept. 3rd, 2017 and Aug. 10th, 2021, respectively, which are images in summer.

Table 1 .
Classification accuracy evaluationAs can be observed from Table2.1, the overall classification accuracy and kappa coefficient of the remote sensing images of the West Coast New Area of Qingdao in 2013 after supervised classification are 98.2792% and 0.9744, respectively; the overall classification accuracy of images and the kappa coefficient in 2017 are 98.

Table 4 .
Dynamic change table from 2013 to 2017

Table 5 .
Dynamic change table from 2017 to 2021 [2] overall pattern of land utilization change in the West Coast New Area of Qingdao is affected by policy factor, leading to an increasing trend of urban building land area.With the increase of building land, the water area was once occupied and destroyed in a large area.In response to it, the government of the West Coast New Area has attached great importance to ecological protection through issuing a series of relevant protection measures and policies since 2018.And remarkable results have been achieved in the ecological protection of the West Coast New Area of Qingdao by the end of September 2021.Socio-economic development: The West Coast New Area of Qingdao has enjoyed a steady growth in economic development year by year since its establishment as a national new area, with GDP accounted for 30.9% of the city's GDP[2]in 2021.Moreover, the building land area was increased by 184.9 square kilometers in the West Coast New Area of Qingdao from 2013 to 2021.Hence, socio-economic development is a significant factor driving the land utilization change of the West Coast New Area of Qingdao.