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Таблица "spatial_ref_sys": порядок записи координат
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#18+
В процессе установки PostGIS создаётся таблица " spatial_ref_sys " с системами координат. Таблица имеет поля " srtext " и " proj4text ". Как по этим данным определить порядок записи координат для определённого SRID ? Например, возьмём классического сферического Меркатора (SRID = 3857 = порядок XY ): PROJCS["WGS 84 / Pseudo-Mercator",GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]],PROJECTION["Mercator_1SP"],PARAMETER["central_meridian",0],PARAMETER["scale_factor",1],PARAMETER["false_easting",0],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["X",EAST],AXIS["Y",NORTH],EXTENSION["PROJ4","+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs"],AUTHORITY["EPSG","3857"]]+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs СК-42, 6-градусная зона №8 (Москва) (SRID = 28408 = порядок YX ): PROJCS["Pulkovo 1942 / Gauss-Kruger zone 8",GEOGCS["Pulkovo 1942",DATUM["Pulkovo_1942",SPHEROID["Krassowsky 1940",6378245,298.3,AUTHORITY["EPSG","7024"]],TOWGS84[23.92,-141.27,-80.9,0,0.35,0.82,-0.12],AUTHORITY["EPSG","6284"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4284"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",45],PARAMETER["scale_factor",1],PARAMETER["false_easting",8500000],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AUTHORITY["EPSG","28408"]]+proj=tmerc +lat_0=0 +lon_0=45 +k=1 +x_0=8500000 +y_0=0 +ellps=krass +towgs84=23.92,-141.27,-80.9,0,0.35,0.82,-0.12 +units=m +no_defs Классическая географическая система координат (SRID = 4326 = порядок YX ): GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]]+proj=longlat +datum=WGS84 +no_defs Какие параметры в полях " srtext " и " proj4text " отвечают за порядок записи координат ? ... |
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12.01.2021, 21:15 |
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