The Gridded Population of World Version 4 (GPWv4) models the distribution of global human population for the years 2000, 2005, 2010, 2015, and 2020 on 30 arc-second (approximately 1km) grid cells. Population is distributed to cells using proportional allocation of population from census and administrative units. Population input data are collected at the most detailed spatial resolution available from the results of the 2010 round of censuses, which occurred between 2005 and 2014. The input data are extrapolated to produce population estimates for each modeled year.
These ancillary data grids contain additional per-pixel data that can be used to assess the quality of the population estimates and how they were produced.
代码语言：javascript复制世界第 4 版网格人口 (GPWv4) 对 2000、2005、2010、2015 和 2020 年在 30 弧秒（约 1 公里）网格单元上的全球人口分布进行建模。使用人口普查和行政单位的人口比例分配将人口分配到单元格。人口输入数据是在 2010 年普查结果中可用的最详细的空间分辨率收集的，普查结果发生在 2005 年和 2014 年之间。输入数据被外推以产生每个建模年份的人口估计值。
这些辅助数据网格包含额外的每像素数据，可用于评估人口估计的质量及其产生方式。Dataset Availability
2000-01-01T00:00:00 - 2020-01-01T00:00:00
Dataset Provider
CIESIN
Collection Snippet
ee.Image("CIESIN/GPWv4/ancillary-data-grids")
Resolution
30 arc seconds
Bands Table
Name | Description | Min* | Max* | Units |
|---|---|---|---|---|
water-mask | Water mask | |||
water-mask Bitmask | Bit 0: Identifies water pixels; non-water pixels are masked 0: Total water pixels that are completely water and/or permanent ice.1: Partial water pixels that also contain land. | |||
data-context | Categorizes pixels with estimated zero population based on information provided in the census documents. | |||
mean-administrative-unit-area | The mean area of the input unit(s) from which population count and density grids are created. | 0 | 816831 | km^2 |
national-identifier | An integer that represents the census data source used to produce the GPWv4 population estimates. Pixels (grid cells) that have the same value reflect the same data source, most often a country or territory. Note that these data represent the area covered by the statistical data as provided, and are not official representations of country or territory boundaries. | 4 | 999 | |
land-area | Estimate of the land area, excluding permanent ice and water, within each 30 arc-second pixel. | 0 | 0.86 | km^2 |
water-area | Estimate of the water area (permanent ice and water) within each 30 arc-second pixel. | 0 | 0.86 | km^2 |
- Bit 0: Identifies water pixels; non-water pixels are masked
- 0: Total water pixels that are completely water and/or permanent ice.
- 1: Partial water pixels that also contain land.
data-contextCategorizes pixels with estimated zero population based on information provided in the census documents.mean-administrative-unit-areaThe mean area of the input unit(s) from which population count and density grids are created.0816831km^2national-identifierAn integer that represents the census data source used to produce the GPWv4 population estimates. Pixels (grid cells) that have the same value reflect the same data source, most often a country or territory. Note that these data represent the area covered by the statistical data as provided, and are not official representations of country or territory boundaries.4999land-areaEstimate of the land area, excluding permanent ice and water, within each 30 arc-second pixel.00.86km^2water-areaEstimate of the water area (permanent ice and water) within each 30 arc-second pixel.00.86km^2
* = Values are estimated
Class Table: data-context
Value | Color | Color Value | Description |
|---|---|---|---|
201 | #099506 | Park or protected area. | |
202 | #ff0b00 | Military district, airport zone, or other infrastructure. | |
203 | #060606 | Not enumerated or not reported in census. | |
204 | #a5a5a5 | No households. | |
205 | #ffe152 | Uninhabited. |
数据引用：
Center for International Earth Science Information Network - CIESIN - Columbia University. 2016. Gridded Population of the World, Version 4 (GPWv4): Administrative Unit Center Points with Population Estimates. Palisades, NY: NASA Socioeconomic Data and Applications Center (SEDAC). https://doi.org/10.7927/H4F47M2C. Accessed DAY MONTH YEAR.
Center for International Earth Science Information Network - CIESIN - Columbia University. 2016. Gridded Population of the World, Version 4 (GPWv4): Land and Water Area. Palisades, NY: NASA Socioeconomic Data and Applications Center (SEDAC). https://doi.org/10.7927/H45M63M9. Accessed DAY MONTH YEAR.
Center for International Earth Science Information Network - CIESIN - Columbia University. 2016. Gridded Population of the World, Version 4 (GPWv4): National Identifier Grid. Palisades, NY: NASA Socioeconomic Data and Applications Center (SEDAC). https://doi.org/10.7927/H41V5BX1. Accessed DAY MONTH YEAR.
代码：
代码语言：javascript复制var dataset = ee.Image('CIESIN/GPWv4/ancillary-data-grids');
var zeroPopulationAreas = dataset.select('data-context');
var zeroPopulationAreasVis = {
min: 201.0,
max: 205.0,
palette: ['099506', 'ff0b00', '060606', 'a5a5a5', 'ffe152'],
};
Map.setCenter(-3.3, 36.03, 1);
Map.addLayer(
zeroPopulationAreas, zeroPopulationAreasVis, 'Zero Population Areas');
