using System;
using System.Collections.Generic;
using System.Text;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.esriSystem;
using System.Runtime.InteropServices;
using KGIS.Framework.AE.GaussCalculate;

namespace Kingo.Plugin.General.Helper
{
    /// <summary>
    /// 计算椭球面积入口
    /// </summary>
    public class ATEllipseArea
    {
        //private ISpatialReference pSpatialReference;
        public ATEllipseArea() { }

        /// <summary>
        /// 获得单个多边形椭球面积 
        /// </summary>
        /// <param name="pIPolygon">多边形</param>
        /// <returns>该多边形面积</returns>
        public static double GetPolygonArea(IPolygon pIPolygon)
        {
            try
            {
                // 1、获得投影
                String SphName = pIPolygon.SpatialReference.Name.ToString().ToUpper();
                // 2、获得椭球
                ICoordinate coordinate = CoordinateFactory.CreateCoordinate();
                if (SphName.Contains("XIAN_1980") || SphName.Contains("XIAN1980"))
                {
                    coordinate = CoordinateFactory.CreateCoordinate((KGIS.Framework.AE.GaussCalculate.Spheroid)KGIS.Framework.AE.GaussCalculate.Spheroid.SphXian80);
                }
                else if (SphName.Contains("BEIJING_1954") || SphName.Contains("BEIJING1954"))
                {
                    coordinate = CoordinateFactory.CreateCoordinate((KGIS.Framework.AE.GaussCalculate.Spheroid)KGIS.Framework.AE.GaussCalculate.Spheroid.SphBeijing54);
                }
                else if (SphName.Contains("WGS_1984") || SphName.Contains("WGS1984"))
                {
                    coordinate = CoordinateFactory.CreateCoordinate((KGIS.Framework.AE.GaussCalculate.Spheroid)KGIS.Framework.AE.GaussCalculate.Spheroid.SphWGS84);
                }
                else if (SphName.Contains("CGCS_2000") || SphName.Contains("CGCS2000"))
                {
                    coordinate = CoordinateFactory.CreateCoordinate((KGIS.Framework.AE.GaussCalculate.Spheroid)KGIS.Framework.AE.GaussCalculate.Spheroid.SphCGCS2000);
                }
                else
                {
                    return -1;
                }
                // 3、计算面积
                IGeometry pGeometry = pIPolygon as IGeometry;
                double PolygonArea = 0.0;
                // 4、保留两位小数
                double a = coordinate.CalculateTerranArea(pGeometry);
                PolygonArea = Math.Round(a, 2, MidpointRounding.AwayFromZero);
                return PolygonArea;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

    }
}