Simplification.NET

C# wrapper for Rust library by urschrei for Ramer-Douglas-Peucker and Visvalingam-Whyatt algorithms.

Usage

using Simplification.Algorithms;

double[][] input = [
    [0.0, 0.0],
    [5.0, 4.0],
    [11.0, 5.5],
    [17.3, 3.2],
    [27.8, 0.1],
];

ISimplificationAlgorithm rdpAlgorithm = new RdpAlgorithm();

// For RDP, Try an epsilon of 1.0 to start with. Other sensible values include 0.01, 0.001
double[][] simplified = rdpAlgorithm.Simplify(input, 1.0); // returns simplified data
UIntPtr[] simplifiedIndices = rdpAlgorithm.SimplifyIdx(input, 1.0); // returns simplified indices

ISimplificationAlgorithm visvAlgorithm = new VisvalingamWhyattAlgorithm();

simplified = visvAlgorithm.Simplify(input, 1.0); // returns simplified data
simplifiedIndices = visvAlgorithm.SimplifyIdx(input, 1.0); // returns simplified indices

simplified = ((VisvalingamWhyattAlgorithm)visvAlgorithm)
    .PreserveTopologySimplify(input, 1.0); // returns simplified data, while preserving topology
	
simplified = ((VisvalingamWhyattAlgorithm)visvAlgorithm)
    .SimplifyMemOptimized(input, 1.0); // returns simplified data but uses less memory

Warning

Even though Visvalingam.Simplify and Visvalingam.SimplifyMemOptimized use the same algorithm output is different, maybe I will fix this in the future. But both methods get thing done properly, SimplifyMemOpt is more aggresive.

Benchmarks

Platform

BenchmarkDotNet v0.13.12, Windows 10 (10.0.19045.4529/22H2/2022Update)
12th Gen Intel Core i7-12700, 1 CPU, 20 logical and 12 physical cores
.NET SDK 8.0.300
  [Host]     : .NET 8.0.5 (8.0.524.21615), X64 RyuJIT AVX2
  DefaultJob : .NET 8.0.5 (8.0.524.21615), X64 RyuJIT AVX2

Ramer-Douglas Peucker algorithm

Method	Mean	Error	StdDev	Median	Gen0	Gen1	Gen2	Allocated
SimplifyRdp_vals_500_toler_0_1	106.16 μs	6.205 μs	18.295 μs	113.56 μs	3.7842	-	-	48.54 KB
SimplifyRdp_vals_500_toler_0_5	94.41 μs	3.782 μs	11.152 μs	98.04 μs	3.4180	-	-	44.18 KB
SimplifyRdp_vals_500_toler_0_9	31.30 μs	0.617 μs	0.547 μs	31.30 μs	2.9297	-	-	37.71 KB
SimplifyRdp_vals_1000_toler_0_1	239.14 μs	11.894 μs	35.070 μs	255.49 μs	7.5684	0.2441	-	98.32 KB
SimplifyRdp_vals_1500_toler_0_1	361.03 μs	22.244 μs	65.588 μs	391.00 μs	11.4746	0.7324	-	146.98 KB
SimplifyRdpIdx_vals_500_toler_0_1	96.52 μs	5.950 μs	17.545 μs	104.72 μs	2.9297	-	-	37.45 KB
SimplifyRdpIdx_vals_500_toler_0_5	83.16 μs	5.058 μs	14.914 μs	88.48 μs	2.8687	-	-	36.73 KB
SimplifyRdpIdx_vals_500_toler_0_9	32.21 μs	0.352 μs	0.329 μs	32.16 μs	2.7466	-	-	35.65 KB
SimplifyRdpIdx_vals_1000_toler_0_1	98.14 μs	3.687 μs	10.871 μs	101.13 μs	2.9297	-	-	37.45 KB
SimplifyRdpIdx_vals_1500_toler_0_1	97.62 μs	4.421 μs	13.036 μs	101.07 μs	2.9297	-	-	37.45 KB
SimplifyRdp_vals_12000_toler_0_1	2,924.44 μs	232.488 μs	685.497 μs	3,066.83 μs	89.8438	27.3438	27.3438	1115.11 KB
SimplifyRdpIdx_vals_12000_toler_0_1	2,876.09 μs	140.119 μs	413.143 μs	2,997.48 μs	74.2188	29.2969	29.2969	889.06 KB

Visvalingam-Whyatt algorithm

Method	Mean	Error	StdDev	Median	Gen0	Gen1	Gen2	Allocated
SimplifyVw_vals_500_toler_0_5	66.139 μs	6.6480 μs	19.6018 μs	48.873 μs	3.4180	-	-	44.18 KB
SimplifyVw_vals_500_toler_1_5	56.721 μs	0.8290 μs	0.7349 μs	56.861 μs	3.1128	-	-	40.38 KB
SimplifyVw_vals_500_toler_3	104.847 μs	5.0088 μs	14.7685 μs	111.347 μs	2.9297	-	-	37.62 KB
SimplifyVw_vals_1000_toler_0_5	178.975 μs	12.2477 μs	36.1126 μs	196.876 μs	6.7139	0.1221	-	86.13 KB
SimplifyVw_vals_1500_toler_0_5	293.125 μs	12.3395 μs	36.3833 μs	306.644 μs	10.0098	0.4883	-	130.8 KB
SimplifyVwIdx_vals_500_toler_0_5	75.208 μs	2.7263 μs	8.0384 μs	77.788 μs	2.8687	-	-	36.73 KB
SimplifyVwIdx_vals_500_toler_1_5	93.081 μs	3.3618 μs	9.9122 μs	96.659 μs	2.8076	-	-	36.09 KB
SimplifyVwIdx_vals_500_toler_3	101.466 μs	4.1660 μs	12.2836 μs	105.068 μs	2.7466	-	-	35.63 KB
SimplifyVwIdx_vals_1000_toler_0_5	139.699 μs	13.4006 μs	39.5119 μs	143.750 μs	5.6152	0.1221	-	73.02 KB
SimplifyVwIdx_vals_1500_toler_0_5	154.101 μs	2.8969 μs	2.8451 μs	153.841 μs	8.5449	0.2441	-	109.76 KB
SimplifyPT_vals_500_toler_0_5	640.235 μs	8.5795 μs	7.6055 μs	639.373 μs	2.9297	-	-	42.21 KB
SimplifyPT_vals_500_toler_1_5	749.852 μs	6.4272 μs	6.0120 μs	749.961 μs	2.9297	-	-	39.07 KB
SimplifyPT_vals_500_toler_3	811.441 μs	7.3295 μs	6.8561 μs	809.506 μs	2.9297	-	-	37.43 KB
SimplifyPT_vals_1000_toler_0_5	1,514.120 μs	7.7500 μs	7.2494 μs	1,512.980 μs	5.8594	-	-	84.73 KB
SimplifyPT_vals_1500_toler_0_5	1,799.576 μs	14.5928 μs	13.6501 μs	1,798.862 μs	9.7656	-	-	128.98 KB
SimplifyOpt_vals_500_toler_0_5	8.923 μs	0.1051 μs	0.0932 μs	8.896 μs	0.3052	-	-	3.96 KB
SimplifyOpt_vals_500_toler_1_5	15.387 μs	0.0635 μs	0.0530 μs	15.392 μs	0.3052	-	-	3.96 KB
SimplifyOpt_vals_500_toler_3	16.740 μs	0.3060 μs	0.2862 μs	16.630 μs	0.3052	-	-	3.96 KB
SimplifyOpt_vals_1000_toler_0_5	26.365 μs	0.3936 μs	0.3489 μs	26.364 μs	0.6104	-	-	7.87 KB
SimplifyOpt_vals_1500_toler_0_5	53.622 μs	0.8641 μs	0.7660 μs	53.608 μs	0.9155	-	-	11.77 KB
SimplifyVw_vals_12000_toler_0_5	2,083.612 μs	41.0960 μs	47.3263 μs	2,086.235 μs	85.9375	27.3438	27.3438	1015.87 KB
SimplifyVwIdx_vals_12000_toler_0_5	1,982.066 μs	37.0464 μs	34.6532 μs	1,984.961 μs	62.5000	27.3438	27.3438	872.52 KB
SimplifyVwPT_vals_12000_toler_0_5	20,077.673 μs	293.1432 μs	259.8638 μs	20,038.420 μs	62.5000	-	-	1004.39 KB
SimplifyVwOpt_vals_12000_toler_0_5	4,059.296 μs	78.3011 μs	80.4094 μs	4,053.321 μs	140.6250	140.6250	23.4375	93.83 KB

Simplified line

Before simplification

After simplification

RDP 5 tolerance

Visvalingam 10 tolerance

Visvalingam preserve topology 10 tolerance

Visvalingam memory optimized 10 tolerance

Package

https://www.nuget.org/packages/Simplification/1.1.0