scholarly journals Dot Symbol Auto-Filling Method for Complex Areas Considering Shape Features

2019 ◽  
Vol 8 (3) ◽  
pp. 158
Author(s):  
Yong Yin ◽  
Chengming Li ◽  
Pengda Wu
Keyword(s):  
Land Use ◽  
Guizhou Province ◽  
Regular Pattern ◽  
Shape Features ◽  
National Data ◽  
Tile Type ◽  
Filling Method ◽  
Inner Region ◽  
Point Type ◽  
Point Level

Filling dot maps with a regular pattern is a key step in visual representation of land use data. The traditional methods cannot adapt well to shape features of complex areas, leading to an unreasonable symbol arrangement in the inner region and area boundaries during symbol filling. For this reason, a dot symbol auto-filling method of complex areas considering shape features is proposed in this paper. First, based on the constrained Delaunay triangulation, the internal structure of a complex area is divided into three simple filling areas denoted tile type, narrow type, and point type. Next, according to the geometric shape features, these three type areas are filled with plane, line, and point level of symbols respectively. Finally, the dot symbols near to boundaries are adjusted on the basis of the boundary constraint to optimize the symbol-filling effect. Based on the national data of a region in Guizhou Province, the method proposed in this paper is compared to the traditional symbol filling methods for validation. The experimental results show that the proposed method improves the dot symbol sufficiency of complex areas, and the edge of dot symbol group closely adhere to the boundary and conform to the extension characteristics of boundary without creating spatial conflicts such as spatial overlap, the filling result can better reflect the shape features of the areas.

scholarly journals Dot Symbol Auto-filling Method for Land-use Areas in Cartographic Representation

2019 ◽  
Vol 1 ◽  
pp. 1-1
Author(s):  
Yong Yin ◽  
Chengcheng Zhang
Keyword(s):  
Land Use ◽  
Traditional Method ◽  
Guizhou Province ◽  
Shape Features ◽  
National Data ◽  
Tile Type ◽  
Filling Method ◽  
Point Line ◽  
Inner Region ◽  
Point Type

<p><strong>Abstract.</strong> Dot symbol filling is a key step in the visualization of land use areas data. The traditional method cannot adapt well to the shape features of complex areas, which leads to the unreasonable symbol arrangement in the inner region and boundary of areas during symbol filling. For this reason, a dot symbol auto-filling method for land-use areas considering shape features is proposed in this paper. Firstly, based on the constrained Delaunay triangulation, the internal structure of complex areas is branched and the paragraphs with the same width and narrowness features in the branch are extracted to realize the fine division of complex areas. Then, according to the geometric shape features of the segment, it is divided into three types, i.e., tile type, narrow type and point type, filled with three levels of symbols: point, line and plane respectively. Finally, the internal and external buffer constraints are set to process the symbols at the boundary of areas to optimize the filling effect of boundary symbols. Based on the national data of a region in Guizhou Province, the method in this paper is compared with the traditional symbol filling methods for validation. The experimental results show that the proposed method has better filling fullness for symbol filling of complex areas, and the symbols at the boundary fit areas contour without creating spatial conflicts such as cover, and the filling result can better reflect the shape features of the areas.</p>

scholarly journals Spatio-temporal variation of water supply in Guizhou Province, China

Water Policy ◽  
2016 ◽  
Vol 19 (1) ◽  
pp. 181-195 ◽  
Author(s):  
Huiqing Han ◽  
Yuxiang Dong
Keyword(s):  
Land Use ◽  
Water Supply ◽  
Urban Expansion ◽  
Guizhou Province ◽  
Water Yield ◽  
Freshwater Ecosystem ◽  
Yield Model ◽  
Invest Model ◽  
Spatio Temporal ◽  
The Impact

Water supply is an important freshwater ecosystem service provided by ecosystems. Water shortages resulting from spatio-temporal heterogeneity of climate condition or human activities present serious problems in the Guizhou Province of southwest China. This study aimed to analyze the spatio-temporal changes of water supply service using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, explore how climate and land-use changes impact water supply provision, and discuss the impact of parameters associated with climate and land-use in the InVEST model on water supply in the region. We used data and the model to forecast trends for the year 2030 and found that water supply has been declining in the region at the watershed scale since 1990. Climate and land-use change played important roles in affecting the water supply. Water supply was overwhelmingly driven by the reference evapotranspiration and annual average precipitation, while the plant evapotranspiration coefficients for each land-use type had a relatively small effect. The method for sensitivity analysis developed in this study allowed exploration of the relative importance of parameters in the InVEST water yield model. The Grain-for-Green project, afforestation, and urban expansion control should be accelerated in this region to protect the water supply.

scholarly journals Quantifying Land Use/Land Cover and Landscape Pattern Changes and Impacts on Ecosystem Services

2019 ◽  
Vol 17 (1) ◽  
pp. 126 ◽  
Author(s):  
Qingjian Zhao ◽  
Zuomin Wen ◽  
Shulin Chen ◽  
Sheng Ding ◽  
Minxin Zhang
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Landscape Heterogeneity ◽  
Landscape Patterns ◽  
Water Bodies ◽  
Guizhou Province ◽  
Land Use Land Cover ◽  
Residential Areas ◽  
Regulatory Policies ◽  
Land Types

Based on satellite remote sensing image, GIS and Fragstats, this study modeled and calculated the dynamic changes of land use, land cover and landscape patterns in Guizhou Province, China, and calculated the changes of ecosystem service values (ESVs). The impacts of the evolution of landscape patterns on the ESVs were analyzed, and reasonable policy recommendations were made. The findings are as follows: (1) In the past two decades, the area of cropland and grassland has decreased; the area of water bodies, urban and rural, industrial and mining, and residential areas has increased; the area of forestland has increased first and then decreased. (2) The two major types of landscapes, cropland and grassland, are clearly being replaced by two land types, forest land and water bodies. (3) Overall, the degree of landscape aggregation and adjacency has decreased, and the landscape heterogeneity has increased. (4) The total amount of ESV in 2000, 2008, 2013 and 2017 was 2574 × 108 Yuan RMB, 2605 × 108 Yuan RMB, 2618 × 108 Yuan RMB and 2612 × 108 Yuan RMB, respectively. The changes of landscape patterns had important impacts on the ESVs. In order to solve the problems caused by the increasingly prominent changes in the landscape patterns and improve the ESVs, it is necessary to rationally plan and allocate land resources, optimize the industrial structures, and develop effective regulatory policies.

scholarly journals Discrepancies in Karst Soil Organic Carbon in Southwest China for Different Land Use Patterns: A Case Study of Guizhou Province

2019 ◽  
Vol 16 (21) ◽  
pp. 4199
Author(s):  
Zhenming Zhang ◽  
Xianfei Huang ◽  
Yunchao Zhou ◽  
Jiachun Zhang ◽  
Xubo Zhang
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Type ◽  
Southwest China ◽  
Potassium Dichromate ◽  
Soil Samples ◽  
Guizhou Province ◽  
Land Uses ◽  
Karst Areas

The assessment of soil organic carbon (SOC) in mountainous karst areas is very challenging, due to the high spatial heterogeneity in SOC content and soil type. To study and assess the SOC storage in mountainous karst areas, a total of 22,786 soil samples were collected from 2,854 soil profiles in Guizhou Province in Southwest China. The SOC content in the soil samples was determined by the oxidation of potassium dichromate (K2Cr2O7), followed by titration with iron (II) sulfate (FeSO4). The SOC storage was assessed based on different land uses. The results suggested that the average SOC density in the top 1.00 m of soil associated with different land uses decreased in the following order: Croplands (9.58 kg m−2) > garden lands (9.07 kg m−2) > grasslands (8.07 kg m−2) > forestlands (7.35 kg m−2) > uncultivated lands (6.94 kg m−2). The SOC storage values in the 0.00–0.10 m, 0.00–0.20 m, 0.00–0.30 m and 0.00–1.00 m soil layers of Guizhou Province were 0.50, 0.87, 1.11 and 1.58 Pg, respectively. The SOC in the top 0.30 m of soil accounted for 70.25% of the total within the 0.00–1.00 m layer in Guizhou Province. It was concluded that assessing SOC storage in mountainous karst areas was more accurate when using land use rather than soil type. This result can supply a scientific reference for the accurate assessment of the SOC storage in the karst areas of southwestern China, the islands of Java, northern and central Vietnam, Indonesia, Kampot Province in Cambodia and in the general area of what used to be Yugoslavia, along with other karst areas with similar ecological backgrounds.

Spatial-temporal evolution of land use and landscape pattern of the mountain-basin system in Guizhou Province

2014 ◽  
Vol 34 (12) ◽  
Author(s):  
李阳兵 LI Yangbing ◽  
姚原温 YAO Yuanwen ◽  
谢静 XIE Jing ◽  
王发艳 WANG Fayan ◽  
白晓永 BAI Xiaoyong
Keyword(s):  
Land Use ◽  
Landscape Pattern ◽  
Temporal Evolution ◽  
Guizhou Province ◽  
Basin System

Improving the spatial resolution and ecostratification of crop yield estimates in Canada

2015 ◽  
Vol 95 (3) ◽  
pp. 287-297 ◽  
Author(s):  
Yuneng Du ◽  
Ted Huffman ◽  
Bahram Daneshfar ◽  
Melodie Green ◽  
Feng Feng ◽  
...  
Keyword(s):  
Land Use ◽  
Crop Yield ◽  
Spatial Resolution ◽  
Crop Insurance ◽  
Climatic Conditions ◽  
National Data ◽  
Yield Data ◽  
High Level ◽  
Insurance Data ◽  
Broad Level

Du, Y., Huffman, T., Daneshfar, B., Green, M., Feng, F., Liu, J., Liu, T. and Liu, H. 2015. Improving the spatial resolution and ecostratification of crop yield estimates in Canada. Can. J. Soil Sci. 95: 287–297. Canada's terrestrial ecostratification framework provides nested spatial units for organizing national data related to soils, landforms and land use. In the agricultural domain, the lack of national, uniform crop yield data on the ecostratification framework severely hinders our ability to evaluate the biophysical data with respect to economic and climatic conditions. We developed a national crop yield database at the regional (ecodistrict) level by aggregating individual records of an existing but very broad-level sample-derived yield database according to the ecostratification hierarchy. Issues related to the different sampling frameworks and the need for confidentiality of individual records were resolved in order to generate an ecostratified crop yield dataset at a reasonably detailed spatial scale. Sixty crops were first statistically arranged into 37 agronomically similar crop groups in order to increase class size, and these crop groups were aggregated into increasingly large spatial units until confidentiality was assured. The methodology maintained data quality and confidentiality while producing crop yield estimates at the ecodistrict level. Comparison to independent crop insurance data confirmed that the resulting crop yield data are valid where estimates were derived from data released at the level of an ecodistrict or an ecoregion, but not at the ecoprovince level. Our crop yield estimates offer a reasonably high level of spatial precision while remaining within standard confidentiality constraints.

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