问如何用坐标和方位角在PostGis中建立扇形楔(扇形)？
EN

Stack Overflow用户

提问于 2022-07-20 11:45:07

回答 2查看 185关注 0票数 2

我找不到正确的答案，试图在PostGis中创建函数，该函数返回几何类型的多边形。该函数可用于在地图上可视化蜂窝网络拓扑结构。下面你可以找到PostGis的这个函数，它有下一个输入参数: lon，lat，方位，距离，宽度。馅饼的距离长度；馅饼的宽度。

create or replace function sector_3(lon float, lat float, azimuth float, distance integer, width integer)
returns geometry
language plpgsql
as
$$
declare
   sector geometry;
begin
    sector = ST_MakePolygon(ST_MakeLine(ARRAY[ST_SetSRID(ST_MakePoint(lon,lat),4326),
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth-(width/2))/180.0)::geometry,
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth-(width/2-1*(width/2/5)))/180.0)::geometry,
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth-(width/2-2*(width/2/5)))/180.0)::geometry,
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth-(width/2-3*(width/2/5)))/180.0)::geometry,
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth-(width/2-4*(width/2/5)))/180.0)::geometry,
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth)/180.0)::geometry,
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth+(width/2-4*(width/2/5)))/180.0)::geometry,
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth+(width/2-3*(width/2/5)))/180.0)::geometry,
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth+(width/2-2*(width/2/5)))/180.0)::geometry,
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth+(width/2-1*(width/2/5)))/180.0)::geometry,
                ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, pi()*(azimuth+(width/2))/180.0)::geometry,                                   
                ST_SetSRID(ST_MakePoint(lon,lat),4326)  
                     ]));
   return sector;
end;
$$;

因此，您将看到扇区，它从给定的点(龙，lat)和给定的距离(长度)和宽度开始。

sql

postgresql

postgis

Stack Overflow用户

发布于 2022-10-06 06:09:45

create or replace function sector_make(lon float, lat float, azimuth float, distance integer, width integer)
returns geometry
language plpgsql
as
$$
declare
   sector geometry;
   i integer;
 begin
  sector =  ST_SetSRID(ST_MakePoint(lon,lat),4326);  
    for i in  (select 0-width/2)..(select width/2) 
    loop
        sector=ST_UNION(sector,ST_Project(ST_SetSRID(ST_MakePoint(lon,lat),4326)::geography, distance, radians(azimuth+i))::geometry);
    end loop;    
 return ST_MakePolygon(ST_MakeLine(ARRAY[sector,ST_SetSRID(ST_MakePoint(lon,lat),4326)]));
end;
$$;

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原文链接：

https://stackoverflow.com/questions/73051042

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