RhumbPanel.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using NETGeographicLib;

namespace Projections
{
    public partial class RhumbPanel : UserControl
    {
        Rhumb m_rhumb;
        public RhumbPanel()
        {
            InitializeComponent();
            m_rhumb = Rhumb.WGS84();
            m_Lat1TextBox.Text = "32";
            m_lon1TextBox.Text = "-86";
            m_lat2TextBox.Text = "33";
            m_lon2TextBox.Text = "-87";
            OnIndirect(this, null);
        }

        private void OnDirect(object sender, EventArgs e)
        {
            try
            {
                double lat1 = Double.Parse( m_Lat1TextBox.Text );
                double lon1 = Double.Parse( m_lon1TextBox.Text );
                double s12 = Double.Parse( m_s12TextBox.Text );
                double azimuth = Double.Parse( m_azimuthTextBox.Text );
                double lat2, lon2;
                m_rhumb.Direct(lat1, lon1, azimuth, s12, out lat2, out lon2);
                m_lat2TextBox.Text = lat2.ToString();
                m_lon2TextBox.Text = lon2.ToString();
                GeneratePoints(lat1, lon1, azimuth, 0.25 * s12);
            }
            catch (Exception xcpt )
            {
                MessageBox.Show( xcpt.Message, "Invalid input", MessageBoxButtons.OK, MessageBoxIcon.Error );
            }
        }

        private void OnIndirect(object sender, EventArgs e)
        {
            try
            {
                double lat1 = Double.Parse(m_Lat1TextBox.Text);
                double lon1 = Double.Parse(m_lon1TextBox.Text);
                double lat2 = Double.Parse(m_lat2TextBox.Text);
                double lon2 = Double.Parse(m_lon2TextBox.Text);
                double s12, azimuth;
                m_rhumb.Inverse(lat1, lon1, lat2, lon2, out s12, out azimuth);
                m_s12TextBox.Text = s12.ToString();
                m_azimuthTextBox.Text = azimuth.ToString();
                GeneratePoints(lat1, lon1, azimuth, 0.25 * s12);
            }
            catch (Exception xcpt)
            {
                MessageBox.Show(xcpt.Message, "Invalid input", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        private void GeneratePoints( double lat1, double lon1, double azimuth, double space )
        {
            RhumbLine line = m_rhumb.Line(lat1, lon1, azimuth);
            m_pointsView.Items.Clear();
            for (int i = 0; i < 5; i++)
            {
                double lat2, lon2;
                line.Position(i * space, out lat2, out lon2);
                string[] items = new string[2] { lat2.ToString(), lon2.ToString() };
                ListViewItem item = new ListViewItem(items);
                m_pointsView.Items.Add(item);
            }
        }

        private void OnValidate(object sender, EventArgs e)
        {
            try
            {
                Rhumb r = new Rhumb(NETGeographicLib.Constants.WGS84.EquatorialRadius, NETGeographicLib.Constants.WGS84.Flattening, true);
                double lat1 = 32.0, lon1 = -86.0, azi12 = 45.0, s12 = 5000.0;
                double lat2, lon2, _s12, _azi12, Area, _Area;
                r.Direct(lat1, lon1, azi12, s12, out lat2, out lon2);
                r.Inverse(lat1, lon1, lat2, lon2, out _s12, out _azi12);
                if ( Test(s12,_s12) || Test(azi12,_azi12))
                    throw new Exception(String.Format("Inverse != Direct: S12 -> {0}, {1}, azi12 -> {2}, {3}", s12, _s12, azi12, _azi12));
                r.Direct(lat1, lon1, azi12, s12, out lat2, out lon2, out Area);
                r.Inverse(lat1, lon1, lat2, lon2, out _s12, out _azi12, out _Area);
                if (Test(s12, _s12) || Test(azi12, _azi12) || Test(Area,_Area))
                    throw new Exception(String.Format("Inverse != Direct: S12 -> {0}, {1}, azi12 -> {2}, {3}, Area -> {4}, {5}", s12, _s12, azi12, _azi12, Area, _Area));

                double _lat2, _lon2;
                RhumbLine l = r.Line(lat1, lon1, azi12);
                l.Position(s12, out _lat2, out _lon2);
                if (Test(lat2,_lat2) || Test(lon2, _lon2))
                    throw new Exception(String.Format("Latitude -> {0}, {1}, Longitude -> {2}, {3}", lat2, _lat2, lon2, _lon2));
                l.Position(s12, out _lat2, out _lon2, out _Area);
                if (Test(lat2, _lat2) || Test(lon2, _lon2) || Test(Area, _Area))
                    throw new Exception(String.Format("Latitude -> {0}, {1}, Longitude -> {2}, {3}, Area -> {4}, {5}", lat2, _lat2, lon2, _lon2, Area, _Area));

                MessageBox.Show("No exceptions detected", "OK", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            catch ( Exception xcpt )
            {
                MessageBox.Show( xcpt.Message, "Exception thrown", MessageBoxButtons.OK, MessageBoxIcon.Error );
            }
        }

        bool Test(double a, double b)
        {
            double delta = a != 0.0 ? Math.Abs((a - b) / a) : Math.Abs(a - b);
            return delta > 1.0e-12;
        }
    }
}