Example #1
0
        public SortedDictionary<double, double> CalculateReduction(SortedDictionary<double, double> input, double percentage)
        {
            if (input.Count <= 2)
            {
                return input;
            }
            else if (percentage<= 0)
            {
                var first = input.First();
                var last = input.Last();
                return new SortedDictionary<double, double>() { {first.Key, first.Value}, {last.Key,last.Value} };
            }
            var m = new MathFunctions();
            var temp = (from n in input select new Point(n.Key, n.Value)).ToList();
            var result = temp.ToList();
            var points = temp.Count;
            double factor = 1.5;
            double calcfactor = Math.Max(1.5, lastfactor / (factor * factor));
            var euclistx = new List<double>();
            for (int i = 0; i < temp.Count - 1; i++)
            {
                euclistx.Add(Math.Sqrt((temp[i].X - temp[i + 1].X) * (temp[i].X - temp[i + 1].X)));
            }
            var thresholdx = Convert.ToDouble(euclistx.Average());

            var thresh = GetAveragePerpendicularDistance(temp);

            var xpercentage = 1.0;
            var difftotal = m.CalculateDifference(temp, new List<Point>() { temp.First(), temp.Last() });
            while (xpercentage > percentage)
            {
                //var intermediate = m.DouglasPeuckerReduction(temp, calcfactor * thresh);
                var intermediate = m.DouglasPeuckerReductionNoStack(temp, calcfactor * thresh);
                
                calcfactor = calcfactor * factor;
                lastfactor = calcfactor;
                var diff = m.CalculateDifference(temp, intermediate);
                xpercentage = 1 - (diff / difftotal);
                if (xpercentage > percentage)
                    result = intermediate.ToList();
            }
            var resultdict = new SortedDictionary<double, double>();
            foreach ( var n in result)
                resultdict.Add(n.X,n.Y);
            return resultdict;
        }
Example #2
0
        public SortedDictionary<double, double> CalculateReduction(SortedDictionary<double, double> input, int amountofpoints)
        {
            if (input.Count <= 2 )
            {
                return input;
            }
            else if (amountofpoints <= 2)
            {
                var first = input.First();
                var last = input.Last();
                return new SortedDictionary<double, double>() { { first.Key, first.Value }, { last.Key, last.Value } };
            }
            var m = new MathFunctions();
            var temp = (from n in input select new Point(n.Key, n.Value)).ToList();
            var result = temp.ToList();
            double factor = 1.5;
            double calcfactor = Math.Max(1.5, lastfactor / (factor * factor));
            var euclistx = new List<double>();
            for (int i = 0; i < temp.Count - 1; i++)
            {
                euclistx.Add(Math.Sqrt((temp[i].X - temp[i + 1].X) * (temp[i].X - temp[i + 1].X)));
            }
            var thresholdx = Convert.ToDouble(euclistx.Average())/100.0;
            var thresh = GetAveragePerpendicularDistance(temp);

            var numberofpoints = input.Count;
            while (numberofpoints >= amountofpoints)
            {
                var intermediate = m.DouglasPeuckerReduction(temp, calcfactor * thresholdx);
                calcfactor = calcfactor * factor;
                lastfactor = calcfactor;
                numberofpoints = intermediate.Count;
                if (numberofpoints >= amountofpoints)
                    result = intermediate.ToList();
            }
            var resultdict = new SortedDictionary<double, double>();
            foreach (var n in result)
                resultdict.Add(n.X, n.Y);
            return resultdict;
        }