scholarly journals Continuous Detection of Surface-Mining Footprint in Copper Mine Using Google Earth Engine

2021 ◽  
Vol 13 (21) ◽  
pp. 4273
Author(s):  
Maoxin Zhang ◽  
Tingting He ◽  
Guangyu Li ◽  
Wu Xiao ◽  
Haipeng Song ◽  
...  

Socioeconomic development is often dependent on the production of mining resources, but both opencast and underground mining harm vegetation and the eco-environment. Under the requirements of the construction for ecological civilization in China, more attention has been paid to the reclamation of mines and mining management. Thus, it is the basement of formulating policies related to mining management and implementing reclamation that detection of mining disturbance rapidly and accurately. This research carries on an empirical study in the Dexing copper mine, Jiangxi, China, aiming at exploring the process of distance and reclamation. Based on the dense time-series stack derived from the Landsat archive on Google Earth Engine (GEE), the disturbance of surface mining in the 1986–2020 period has been detected using the continuous change detection and classification (CCDC) algorithm. The results are that: (1) the overall accuracy of damage and recovery is 92% and 88%, respectively, and the Kappa coefficient is 85% and 84% respectively. This means that we obtained an ideal detection effect; (2) the surface-mining area was increasing from 1986–2020 in the Dexing copper mine, and the accumulation of mining damage is approximately 2865.96 ha with an annual area of 81.88 ha. We also found that the area was fluctuating with the increase. The detected natural restoration was appraised at a total of 544.95 ha in the 1988–2020 period with an average restoration of 16.03 ha. This means that it just restores less in general; (3) it has always been the case that the Dexing mine is damaged by mining and reclamation in the whole year (it is most frequently damaged month is July). All imageries in the mine are detected by the CCDC algorithm, and they are classified as four types by disturbing number in pixel scale (i.e., 0, 1, 2, more than 2 times). Based on that, we found that the only once disturbed pixels account for 64.75% of the whole disturbed pixels, which is the majority in the four classes; (4) this method provides an innovative perspective for obtaining the mining disturbed dynamic information timely and accurately and ensures that the time and number of surface mining disturbed areas are identified accurately. This method is also valuable in other applications including the detection of other similar regions.

2020 ◽  
Vol 12 (10) ◽  
pp. 1612 ◽  
Author(s):  
Wu Xiao ◽  
Xinyu Deng ◽  
Tingting He ◽  
Wenqi Chen

The development and utilization of mining resources are basic requirements for social and economic development. Both open-pit mining and underground mining have impacts on land, ecology, and the environment. Of these, open-pit mining is considered to have the greatest impact due to the drastic changes wrought on the original landform and the disturbance to vegetation. As awareness of environmental protection has grown, land reclamation has been included in the mining process. In this study, we used the Shengli Coalfield in the eastern steppe region of Inner Mongolia to demonstrate a mining and reclamation monitoring process. We combined the Google Earth Engine platform with time series Landsat images and the LandTrendr algorithm to identify and monitor mining disturbances to grassland and land reclamation in open-pit mining areas of the coalfield between 2003 and 2019. Pixel-based trajectories were used to reconstruct the temporal evolution of vegetation, and sequential Landsat archive data were used to achieve accurate measures of disturbances to vegetation. The results show that: (1) the proposed method can be used to determine the years in which vegetation disturbance and recovery occurred with accuracies of 86.53% and 78.57%, respectively; (2) mining in the Shengli mining area resulted in the conversion of 89.98 km2 of land from grassland, water, etc., to barren earth, and only 23.54 km2 was reclaimed, for a reclamation rate of 26.16%; and (3) the method proposed in this paper can achieve fast, efficient identification of surface mining land disturbances and reclamation, and has the potential to be applied to other similar areas.


2020 ◽  
Vol 2 ◽  
Author(s):  
Paulo Arévalo ◽  
Eric L. Bullock ◽  
Curtis E. Woodcock ◽  
Pontus Olofsson

Land cover has been designated by the Global Climate Observing System (GCOS) as an Essential Climate Variable due to its integral role in many climate and environmental processes. Land cover and change affect regional precipitation patterns, surface energy balance, the carbon cycle and biodiversity. Accurate information on land cover and change is essential for climate change mitigation programs such as UN-REDD+. Still, uncertainties related to land change are large, in part due to the use of traditional land cover and change mapping techniques that use one or a few remotely sensed images, preventing a comprehensive analysis of ecosystem change processes. The opening of the Landsat archive and the initiation of the Copernicus Program have enabled analyses based on time series data, allowing the scientific community to explore global land cover dynamics in ways that were previously limited by data availability. One such method is the Continuous Change Detection and Classification algorithm (CCDC), which uses all available Landsat data to model temporal-spectral features that include seasonality, trends, and spectral variability. Until recently, the CCDC algorithm was restricted to academic environments due to computational requirements and complexity, preventing its use by local practitioners. The situation has changed with the recent implementation of CCDC in the Google Earth Engine, which enables analyses at global scales. What is still missing are tools that allow users to explore, analyze and process CCDC outputs in a simplified way. In this paper, we present a suite of free tools that facilitate interaction with CCDC outputs, including: (1) time series viewers of CCDC-generated time segments; (2) a spatial data viewer to explore CCDC model coefficients and derivatives, and visualize change information; (3) tools to create land cover and land cover change maps from CCDC outputs; (4) a tool for unbiased area estimation of key climate-related variables like deforestation extent; and (5) an API for accessing the functionality underlying these tools. We illustrate the usage of these tools at different locations with examples that explore Landsat time series and CCDC coefficients, and a land cover change mapping example in the Southeastern USA that includes area and accuracy estimates.


2021 ◽  
Vol 13 (24) ◽  
pp. 5134
Author(s):  
Junzhi Ye ◽  
Yunfeng Hu ◽  
Lin Zhen ◽  
Hao Wang ◽  
Yuxin Zhang

Large-scale, long time-series, and high-precision land-use mapping is the basis for assessing the evolution and sustainability of ecosystems in Xilingol, the Inner Mongolia Autonomous Region, China. Based on Google Earth Engine (GEE) and Landsat satellite remote-sensing images, the random forest (RF) classification algorithm was applied to create a yearly land-use/land-cover change (LULC) dataset in Xilingol during the past 20 years (2000–2020) and to examine the spatiotemporal characteristics, dynamic changes, and driving mechanisms of LULC using principal component analysis and multiple linear stepwise regression methods. The main findings are summarized as follows. (1) The RF classification algorithm supported by the GEE platform enables fast and accurate acquisition of the LULC dataset, and the overall accuracy is 0.88 ± 0.01. (2) The ecological condition across Xilingol has improved significantly in the last 20 years (2000–2020), and the area of vegetation (grassland and woodland) has increased. Specifically, the area of high-coverage grass and woodland increases (+13.26%, +1.19%), while the area of water and moderate- and low-coverage grass decreases (−15.96%, −7.23%, and −3.27%). Cropland increases first and then decreases (−34.85%) and is mainly distributed in the southeast. The area of deserted land decreases in the south and increases in the center and north, but the total area still decreases (−13.74%). The built-up land expands rapidly (+108.45%). (3) In addition, our results suggest that regional socioeconomic development factors are the primary causes of changes in built-up land, and climate-related factors are the primary causes of water changes, but the correlations between other land-use types and relevant factors are not significant (cropland and grassland). We conclude that the GEE+RF method is capable of automated, long time-series, and high-accuracy land-use mapping, and further changes in climatic, environmental, and socioeconomic development factors, i.e., climate warming and rotational grazing, might have significant implications on regional land surface morphology and landscape dynamics.


Author(s):  
Mauricio Vega-Araya

La Tierra y su biosfera están cambiando constantemente, por lo tanto, es fundamental detectar los cambios con el fin de entender su impacto en los ecosistemas terrestres. Los esquemas de monitoreo de ecosistemas han evolucionado rápidamente en las ultimas décadas. En el caso del monitoreo forestal, los métodos y herramientas que facilitan la utilización de imágenes satelitales permiten realizar este monitoreo con el cual se puede detectar donde y cuando un bosque es eliminado o afectado debido a un evento de deforestación o bien de fuego, lo anterior casi en tiempo real. Estas nuevas herramientas están disponibles para su implementación, sin embargo, ningún paı́s de la región centroamericana y el Caribe ha implementado un sistema como herramienta de decisión dentro de una estructura de gobierno central o federal debido a la ausencia de programas de transferencia de tecnologı́a o programas de capacitación de talento local. Los sensores remotos proporcionan mediciones consistentes y repetibles que permiten la captura de los efectos de muchos procesos que causan el cambio, incluyendo, por ejemplo, incendios, ataques de insectos, agentes de cambio naturales y antropogénicas como por ejemplo, la deforestación, la urbanización, la agricultura, etc. Las series temporales de imágenes de satélite proporcionan maneras para detectar y vigilar cambios en el tiempo y en el espacio, esto consistentemente durante los últimos 30 años a nivel mundial. Los incendios forestales afectan el proceso de sucesión del bosque, no obstante, es muy limitada la existencia de estudios locales que relacionen el efecto de los incendios forestales con las diferencias en la información espectral a partir de sensoramiento remoto. En el presente estudio se plantea y propone la utilización y aprovechamiento de lo que se ha denominado grandes datos, especialmente con el advenimiento muchas plataformas de sensores remotos como Landsat, MODIS y recientemente Sentinel, para identificar cuál es el efecto de los incendios forestales en la sucesión y sus elementos perturbadores, como por ejemplo, la presencia de lianas. Se procesaron las series temporales se usó la plataforma digital Google Earth Engine, que permitió la selección y reducción de la información espacial de los ı́ndices de vegetación en tendencia, estacionalidad y residuos. Se analizó la respuesta de estos ı́ndices en sitios con diferente afectación por incendios forestales. Con estos índices se pretende desarrollar modelos de clasificación de series espaciales de tiempo de los ı́ndices y poder ası́ comprender los cambios en el tiempo y el espacio de los ecosistemas afectados por incendios forestales. Preliminarmente, se encontró una relación entre la incidencia de los incendios forestales y el fenómeno del Niño-Oscilación del Sur para el índice de vegetación denominado índice de área foliar. Además, la evidencia indica que el índice normalizado de vegetación si presenta diferencias respecto a los sitios que tienen un historial de fuegos diferente. El establecer esta relación implica estudiar también los regı́menes de precipitación y temperatura. El descomponer las series de tiempo facilitó la correlación con otras series de tiempo, permitiendo establecer las bases de un monitoreo y a su vez, relacionar las índices de vegetación y su variación con otros elementos climáticos, como por ejemplo, el efecto ENOS.


2018 ◽  
Vol 54(9) ◽  
pp. 29
Author(s):  
Võ Quốc Tuấn ◽  
Nguyễn Thiên Hoa ◽  
Huỳnh Thị Kim Nhân ◽  
Đặng Hoàng Khải

2021 ◽  
Vol 13 (8) ◽  
pp. 1433
Author(s):  
Shobitha Shetty ◽  
Prasun Kumar Gupta ◽  
Mariana Belgiu ◽  
S. K. Srivastav

Machine learning classifiers are being increasingly used nowadays for Land Use and Land Cover (LULC) mapping from remote sensing images. However, arriving at the right choice of classifier requires understanding the main factors influencing their performance. The present study investigated firstly the effect of training sampling design on the classification results obtained by Random Forest (RF) classifier and, secondly, it compared its performance with other machine learning classifiers for LULC mapping using multi-temporal satellite remote sensing data and the Google Earth Engine (GEE) platform. We evaluated the impact of three sampling methods, namely Stratified Equal Random Sampling (SRS(Eq)), Stratified Proportional Random Sampling (SRS(Prop)), and Stratified Systematic Sampling (SSS) upon the classification results obtained by the RF trained LULC model. Our results showed that the SRS(Prop) method favors major classes while achieving good overall accuracy. The SRS(Eq) method provides good class-level accuracies, even for minority classes, whereas the SSS method performs well for areas with large intra-class variability. Toward evaluating the performance of machine learning classifiers, RF outperformed Classification and Regression Trees (CART), Support Vector Machine (SVM), and Relevance Vector Machine (RVM) with a >95% confidence level. The performance of CART and SVM classifiers were found to be similar. RVM achieved good classification results with a limited number of training samples.


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