Vegetation cover (FVC), as an indispensable climate parameter, and the spatial and temporal evolution characteristics of long time series FVC can provide data reference for assessing the surface vegetation condition. MODIS-NDVI data were used to estimate FVC using the image element dichotomous model, and the spatial and temporal evolution characteristics of vegetation cover in Shenyang from 2000 to 2020 were explored by using trend analysis and deviation analysis, while multi-scenario simulation prediction of vegetation cover in Shenyang in 2030 was carried out based on land use data in 2010, 2015 and 2020 combined with PLUS model. The results show that (1) in time, the annual average FVC in Shenyang City increases at a rate of 3.14%/10a, the high and medium-high vegetation cover shows an increasing trend, and the proportion of vegetation improvement area is higher than that of deterioration. (2) Spatially, the high value areas of FVC in Shenyang are mainly distributed in Shenyei New District, Hunnan District and Sujiatun District, while the low value areas are distributed in the five districts and the central part of districts and counties in the city. (3) The simulation results found that: in the historical trend scenario, the area of arable land, forest land, grassland and water area decreased; in the arable land protection scenario, the area of arable land increased and forest land decreased; in the low-carbon development scenario, forest land increased significantly. The results of the study provide a theoretical basis for the future formulation of environmental management policies in Shenyang.

The spatiotemporal big data of urban agglomerations has the characteristics of dynamic and real-time, across time and space, and across administrative regions. The method of traditional small sample data construction brings challenges to the technical aspects of data storage management, integrated analysis, information mining and knowledge discovery. This research is oriented to the major needs of the construction and management of urban agglomerations for key services of spatial information. It focuses on the characteristics of event models and related elements triggered by application subject areas. Based on elements-events-themes, we have designed a spatiotemporal big data framework system for urban agglomeration construction and management with the examples of four subjects. The spatiotemporal big data information resource framework system proposed in this research is helpful to promote the consistency process of spatiotemporal big data in time, space, attributes and scales. This research result will be possible to provide fast data support services for the spatiotemporal information integration application system of urban agglomerations.

Oil palm is a major economic crop and the area of land converted to oil palm cultivation in the tropics has expanded rapidly. Oil palm has become the world's largest source of vegetable oil and it provides tremendous regional economic benefits. However, the expansion of oil palm cultivation has led to the loss of forests, arable land, and peatland, which has caused severe ecological and environmental problems. Application of 3S (RS, GIS, GNSS) technology is useful for the collection, analysis, and management of spatial information, and is essential for both optimizations of the spatial distribution of land use and sustainable development. This paper analyzes the progress of 3S technology application in oil palm research on the basis of a literature review and scientometric analysis. The factors affecting the precision of oil palm mapping are also discussed. We established that papers describing 3S technology application in oil palm research are based primarily on the study of land cover change, and that scientific institutions and researchers in Malaysia, the United States, China, Indonesia, and the United Kingdom are the major contributors. Currently, the application of 3S technology in oil palm research includes oil palm mapping, oil palm land change monitoring, oil palm tree counting, tree age estimation, aboveground biomass and carbon storage estimation, suitability analysis, yield estimation, pest and disease monitoring, and plantation management. The accuracy of mapping is not correlated significantly with the year of publication of specific literature but is correlated with RS data sources and classification methods. The use of 3S technology in oil palm research is currently dominated by RS, which has been used in diverse fields of oil palm research. GIS technology is used mainly for oil palm land change mapping, suitability analysis, plantation management, and pest and disease monitoring, while GNSS is used largely as an additional tool in pest and disease monitoring and plantation management.

Based on a large number of forest litter produciton data and NDVI data, a random forest model was constructed to simulate the spatial and temporal variation characteristics of forest litterfall carbon density in China from 1982 to 2020. The nonlinear relationship between litterfall carbon density and NDVI proves the feasibility of the research method. The simulated results showed a significantly higher positive correlation with the observed values (r=0.65, P <0.001,n=4882), and a smaller error percentage (0.96%), indicating that the simulation accuracy of the random forest model was higher. The temporal and spatial variation characteristics of the carbon density of litters in China during 1982-2020 showed a significant increasing trend (r=0.81, P <0.001), and the carbon density of litters in evergreen coniferous forest, deciduous broad-leaved forest and deciduous coniferous forest increased significantly. It can be seen that long-term continuous NDVI data can effectively simulate and monitor the temporal and spatial dynamics of forest litter carbon density at the national scale, driving advanced random forest models. This provides a new technique for dynamic monitoring of large scale forest litter using remote sensing observation data, and also expands the application scenarios of remote sensing data.

In the background of rapid urbanization and rural revitalization, there is a great significance to optimizing the urban-rural land use structure of metropolises and urban-rural spatial integration development by master the change characteristics of construction land and impervious surface in urban expansion period. Based on the remote sensing monitoring dataset and the internal impervious surface dataset of urban-rural construction land since the 21st century, this research analyzes the structure and impermeable land proportion of urban and rural construction land in Harbin from 2000 to 2015. The purpose is to explore the urban expansion patterns, regional differences, construction land use intensity, and urban-rural differences. The results show that: ①From 2000 to 2015, the urban-rural construction land expanded by 158.32km2 rapidly, the trend of annual gradient and dynamic degree were firstly increased and then decreased. In the same period, from the core area of the city to the far suburbs, the scale of expansion increased in turn, and the construction focus continues move towards to the urban periphery, which shows a spatial heterogeneity obviously. ②The area and proportion of urban construction land and independent industrial and mining land increased year by year, and the sources of expansion were mainly cultivated land. The proportions of rural residential areas decreased by 13.14% from 2000 to 2015, while the structural characteristics of urban-rural construction land changed significantly. ③From 2000 to 2015, the area and proportion of impervious surface in urban-rural construction land increased by 145.32km2 and 10.04% respectively. The land use intensity of urban construction reached a high level, because of the land use intensity of rural residential areas increased rapidly, and the gap between urban and rural areas is narrowing. The proportion of impervious surface was decreasing continuously along the direction of the urban core area to the far suburbs, but the potential for development and utilization was greater in the same direction, because the increment, proportional increment, proportional growth rate and expansion intensity of impermeable surface area was generally increasing. In general, there is a similar trend between the area of impermeable surface and the scale of urban and rural construction land, which can reveal the urban expansion track to a certain extent.