GEOJSON to Topojson Conversion in .NET: Sample Guide

readme.md

GEOJSON to Topojson Conversion in .NET: Sample Guide

Discover how GIS‑focused .NET developers can convert GEOJSON to Topojson with Aspose.GIS for .NET. This guide covers prerequisites, a C# implementation, async streaming, performance tuning for large files, and best‑practice tips, all with a code sample.

Read the full guide here: https://blog.aspose.com/gis/geojson-to-topojson-conversion-in-dotnet-sample-guide/

geojson_to_topojson.cs

using System;
using System.IO;
using System.Threading.Tasks;
using Aspose.Gis;
using Aspose.Gis.Export;
using Aspose.Gis.Geometries;

namespace GeoJsonToTopoJsonDemo
{
    class Program
    {
        static async Task Main(string[] args)
        {
            // Path to the source GEOJSON file
            string geoJsonPath = @"C:\Data\sample.geojson";

            // Output TopoJSON file path
            string topoJsonPath = @"C:\Data\sample.topojson";

            // Load GEOJSON into a VectorLayer
            using (VectorLayer geoLayer = VectorLayer.FromFile(geoJsonPath))
            {
                // Prepare export options
                var options = new TopoJsonExportOptions
                {
                    // Set topology precision (higher = more accurate, larger file)
                    Precision = 0.00001,
                    // Optional: reproject to WGS84 if needed
                    TargetCoordinateSystem = SpatialReferenceSystem.Wgs84
                };

                // Open a file stream for async writing
                using (FileStream outputStream = new FileStream(topoJsonPath, FileMode.Create, FileAccess.Write, FileShare.None, 8192, useAsync: true))
                {
                    // Perform async conversion
                    await geoLayer.ExportToTopoJsonAsync(outputStream, options);
                }
            }

            Console.WriteLine("Conversion completed successfully.");
        }
    }
}