c# – SqlGeography从多边形获取多边形

我有包含相关镇(地理数据类型)的多边形的列TownBoundary的表镇.

对于每个城镇,我获得了生成KML(XML)文件所需的多边形数据,如：

sqlg = SqlGeography.STPolyFromText(new SqlChars(
town.TownBoundary.WellKnownValue.WellKnownText),
town.TownBoundary.CoordinateSystemId);
for (int i = 1; i <= sqlg.STNumPoints(); i++)
{
    SqlGeography point = sqlg.STPointN(i);
    var pLong = (point.Long).ToString().Replace(",", ".");
    var pLat = (point.Lat).ToString().Replace(",", ".");
    double dLong = double.Parse(pLong, CultureInfo.InvariantCulture);
    double dLat = double.Parse(pLat, CultureInfo.InvariantCulture);
    kmlCoordinates.Add(new Vector(dLat, dLong)); //one point od polygon
}

town.TownBoundary.WellKnownValue.WellKnownText的值以POLYGON开头(..

但最近我意识到一些城镇包含更多的多边形而WellKnownText以MULTIPOLYGON开头(..和函数STPolyFromText最终出错.

我把它放在try {}块中,但是在catch {}中 – 如果value是multipolygon – 是否有可能以某种方式获得单个多边形？我知道有方法STMPolyFromText,但我无法在那里处理单个多边形,只有方法STPolyFromText中的点.

我的目标是将多边形分割为多边形,而foreach多边形则采用与上述相同的方法.

解决方法:

解决了它,在方法STMPolyFromText中,我可以使用STNumGeometries获得多边形数组.

sqlg = SqlGeography.STMPolyFromText(
new SqlChars(town.TownBoundary.WellKnownValue.WellKnownText),
town.TownBoundary.CoordinateSystemId);
for (int i = 1; i <= sqlg.STNumGeometries(); i++)
{
 SqlGeography poly = sqlg.STGeometryN(i);
 //foreach poly
} 

标签：c,polygon,geography,sqlgeography
来源： https://codeday.me/bug/20190528/1173111.html