Question

I m new to GIS applications and I have a little problem. I m trying to plot a polygon using geographic coordinates but I need to convert these coordinates to points before I can use them in plotting the polygon. I don t know how to convert these coordinates to points to use for the polygon. I spent all my yesterday finding out how to do this but I really still don t get it. I tried using the geography datatype in ms sql server 2008 but I couldn t find a java api in retrieving the polygon or the converted coordinates. Please help me with a sample code on how to do this.

感谢许多人!

这是我的法典。法典

double earth=6371;
double focal=500;

double lat= 47.653 ;
double lon = -122.358  ;

double latitude = lat*Math.PI/180;
double longitude = lon*Math.PI/180;

double x = earth * Math.sin(latitude)*Math.cos(longitude);

double y = earth * Math.sin(latitude)*Math.sin(longitude);

double z = earth * Math.cos(latitude);

double projectedX = x*focal /(focal+z);

double projectedY = y * focal / (focal+z);

int magx = (int) Math.round(projectedX * 5); 
int magy = (int) Math.round(projectedY *5);

System.out.println ("MAG X : "+magx);
System.out.println ("MAG Y : "+magy);

我只是把魔.X和 y带入我的多角,但没有任何进展。

Answer 1

这是一套n<>/em>坐标的Syntax,用于在服务器中创建和检索一个地理多功能平台:

DECLARE @Polygon geography;
SET @Polygon = geography::STPolyFromText( POLYGON((Lon1 Lat1, Lon2 Lat2, ... Lonn Latn, Lon1 Lat1)) , 4326); 
SELECT @Polygon;

(This assumes you re using geographic coordinates relative to the WGS84 datum. If you don t know what that means, they probably are.)

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