qdgc Yemen

Name: qdgc Yemen
Creator: Zenodo
Published: 2021-01-22T23:58:30+08:00

Zenodo2021-01-23 更新2026-05-25 收录

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https://zenodo.org/record/4458758 数据链接链接失效反馈

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资源简介：

QDGC tables delivered in geopackage file - - - - - - - - - - - - - - - - - - - - - - QDGC represents a way of making (almost) equal area squares covering a specific area to represent specific qualities of the area covered. The squares themselves are based on the degree squares covering earth. Around the equator we have 360 longitudinal lines , and from the north to the south pole we have 180 latitudinal lines. Together this gives us 64800 segments or tiles covering earth. Within each geopackage file you will find a number of tables with these names: -tbl_qdgc_01 -tbl_qdgc_02 -tbl_qdgc_03 -tbl_qdgc_04 -tbl_qdgc_05 -etc The attributes for each table are: qdgc Unique Quarter Degree Grid Cell reference string area_reference Country level_qdgc QDGC level cellsize degrees decimal degree for the longitudal and latitudal length of the cell lon_center Longitude center of the cell lat_center Latitudal center of the cell area_km2 Calculated area for the cell geom Geometry Metadata -------- Geodata GCS_WGS_1984 Datum: D_WGS_1984 Prime Meridian: 0 Areas are calculated with different versions of Albers Equal Area Conic using the PostGIS function st_area. For the African continent I have used Africa Albers Equal Area Conic which will look like this: - st_area(st_transform(geom, 102022))/1000000) Licensing --------- Creative Commons Attribution 4.0 International Conditions ---------- Delivered to the user as-is. No guarantees. If you find errors, please tell me and I will try to fix it. Suggestions for improvements can be addressed to the github repository: https://github.com/ragnvald/qdgc Thankyou -------- The work has over the years been supported and received advice and moral support from many organisations and stakeholders. Here are some of them: - Tanzania Wildlife Research Institute - Dept of Biology, NTNU, Norway - Norwegian Environment Agency - Eivin Røskaft, Steven Prager, Howard Frederick, Julian Blanc, Honori Maliti, Paul Ramsey References ---------- * http://en.wikipedia.org/wiki/QDGC * http://www.mindland.com/wp/projects/quarter-degree-grid-cells/about-qdgc/ * http://en.wikipedia.org/wiki/Lambert_azimuthal_equal-area_projection * http://www.safe.com Ragnvald Larsen Trondheim 23rd of January, 2021 ragnvald@mindland.com www.mindland.com

以地理数据包（GeoPackage）文件交付的QDGC数据表 -------------------------------------------------- 四分度网格单元（Quarter Degree Grid Cell, QDGC）是一种通过覆盖特定区域的近似等面积正方形，来表征该区域特定属性的方法。此类正方形基于覆盖地球的度数网格构建：赤道附近共有360条经线，南北极之间则有180条纬线，二者共同构成了覆盖全球的64800个分区或瓦片。每个地理数据包文件中均包含若干符合命名规则的数据表，命名格式如下： - tbl_qdgc_01 - tbl_qdgc_02 - tbl_qdgc_03 - tbl_qdgc_04 - tbl_qdgc_05 - 以此类推各数据表的属性字段如下： - qdgc：唯一四分度网格单元参考字符串 - area_reference：所属国家/区域 - level_qdgc：QDGC层级 - cellsize：单元格经向与纬向尺寸（单位：十进制度） - lon_center：单元格中心经度 - lat_center：单元格中心纬度 - area_km2：计算得到的单元格面积（单位：平方千米） - geom：几何图形（Geometry） ## 元数据 -------- 地理坐标系：GCS_WGS_1984 基准面：D_WGS_1984 本初子午线：0° 区域面积通过PostGIS的`st_area`函数结合不同版本的阿尔伯斯等面积圆锥投影计算得到。针对非洲大陆，采用了非洲阿尔伯斯等面积圆锥投影，具体计算语句如下： `st_area(st_transform(geom, 102022))/1000000` ## 授权许可 --------- 知识共享署名4.0国际许可协议（Creative Commons Attribution 4.0 International） ## 使用条款 ---------- 本数据集按“现状”提供给用户，不附带任何形式的担保。若发现数据错误，请及时告知，我方将尽力修正。相关改进建议可提交至GitHub仓库：https://github.com/ragnvald/qdgc ## 致谢 -------- 本项目多年来得到了众多机构与相关方的支持与指导，在此一并致谢： - 坦桑尼亚野生动物研究所（Tanzania Wildlife Research Institute） - 挪威科技大学生物系（Dept of Biology, NTNU, Norway） - 挪威环境局（Norwegian Environment Agency） - Eivin Røskaft、Steven Prager、Howard Frederick、Julian Blanc、Honori Maliti、Paul Ramsey ## 参考文献 ---------- * http://en.wikipedia.org/wiki/QDGC * http://www.mindland.com/wp/projects/quarter-degree-grid-cells/about-qdgc/ * http://en.wikipedia.org/wiki/Lambert_azimuthal_equal-area_projection * http://www.safe.com Ragnvald Larsen 特隆赫姆，2021年1月23日 ragnvald@mindland.com www.mindland.com

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创建时间：

2021-01-22

qdgc Yemen

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