HOWTO: Render a map image using the MapGuide Maestro API

RenderMap.dib

#!markdown

# HOWTO: Render a map image using the MapGuide Maestro API

#!markdown

Firstly, add a reference to the [`OSGeo.MapGuide.MaestroAPI`](https://www.nuget.org/packages/OSGeo.MapGuide.MaestroAPI) package on NuGet

#!csharp

#r "nuget:OSGeo.MapGuide.MaestroAPI,*-*"

#!markdown

Then create a new server connection

#!csharp

using OSGeo.MapGuide.MaestroAPI;
using OSGeo.MapGuide.MaestroAPI.Commands;
using OSGeo.MapGuide.MaestroAPI.Services;
using OSGeo.MapGuide.ObjectModels;
using OSGeo.MapGuide.ObjectModels.MapDefinition;
using System.Drawing;
using System.IO;
using Microsoft.DotNet.Interactive.Formatting;

// Change this to match your MapGuide server install as needed
var mapAgentUri = "http://localhost:8018/mapguide/mapagent/mapagent.fcgi";

var conn = ConnectionProviderRegistry.CreateConnection("Maestro.Http",
    "Url", mapAgentUri,
    "Username", "Administrator",
    "Password", "admin");

#!markdown

Then create a runtime map instance and save it to your session repository

#!csharp

var mapSvc = conn.GetService((int)ServiceType.Mapping) as IMappingService;
var resSvc = conn.ResourceService;
var mdf = resSvc.GetResource("Library://Samples/Sheboygan/Maps/Sheboygan.MapDefinition") as IMapDefinition;

double metersPerUnit = 111319.490793274;
var cs = conn.CoordinateSystemCatalog.CreateCoordinateSystem(mdf.CoordinateSystem);
metersPerUnit = cs.MetersPerUnit;

var mid = "Session:" + conn.SessionID + "//TestRendering.Map";
var map = mapSvc.CreateMap(mid, mdf, metersPerUnit);
map.ViewScale = 8000;
map.DisplayWidth = 800;
map.DisplayHeight = 400;
map.DisplayDpi = 96;

map.Save();

#!markdown

Now that you have created the runtime map and saved it to the session repository, pass it to a rendering method

#!csharp

using (var mapImageStream = mapSvc.RenderRuntimeMap(map, map.ViewCenter.X, map.ViewCenter.Y, map.ViewScale, map.DisplayWidth, map.DisplayHeight, map.DisplayDpi, "PNG"))
{
    // For purpose of displaying the result in this interactive notebook, we will convert the stream to a base64 string and
    // pass it to the built-in notebook display facility, but in the context of a web api endpoint, you would return the raw 
    // stream  bytes with the appropriate mime type set
    using (var ms = new MemoryStream())
    {
        await mapImageStream.CopyToAsync(ms);
        ms.Position = 0L;

        string base64str = Convert.ToBase64String(ms.ToArray());
        display(PocketViewTags.img[src: "data:image/png;base64," + base64str]);
    }
}