基于ArcGIS Engine 10.8 设计一个软件，软件的功能包括: (1)GIS数据的加载、显示、查询、量测等GIS软件基本功能; (2)空间插值功能; (3)工具可扩展。给出这个软件的实现步骤和代码。

实现步骤：

1. 创建ArcGIS Engine 10.8工程；
2. 添加需要使用的引用，如ESRI.ArcGIS.Engine、ESRI.ArcGIS.System、ESRI.ArcGIS.Geometry等；
3. 创建地图控件对象，并设置其属性；
4. 加载地图文档，显示地图；
5. 实现GIS数据的查询、量测等基本功能；
6. 实现空间插值功能，可选择使用IDW、Kriging、RBF等算法；
7. 实现工具可扩展功能，可以通过插件方式添加新的工具；
8. 编写代码，实现所有功能。

代码实现：

1. 创建地图控件对象

public partial class Form1 : Form
{
    private AxMapControl axMapControl1;
    public Form1()
    {
        InitializeComponent();
        this.axMapControl1 = new AxMapControl();
        this.axMapControl1.Dock = DockStyle.Fill;
        this.Controls.Add(this.axMapControl1);
    }
}

2. 加载地图文档，显示地图

private void Form1_Load(object sender, EventArgs e)
{
    string filePath = @"D:\MapDocument.mxd";
    if (axMapControl1.CheckMxFile(filePath))
    {
        axMapControl1.LoadMxFile(filePath);
    }
}

3. 实现GIS数据的查询、量测等基本功能

private void btnQuery_Click(object sender, EventArgs e)
{
    IMap map = axMapControl1.Map;
    IActiveView activeView = map as IActiveView;
    ILayer layer = map.get_Layer(0);
    IFeatureLayer featureLayer = layer as IFeatureLayer;
    IFeatureClass featureClass = featureLayer.FeatureClass;
    IQueryFilter queryFilter = new QueryFilterClass();
    queryFilter.WhereClause = "NAME = '北京市'";
    IFeatureCursor featureCursor = featureClass.Search(queryFilter, false);
    IFeature feature = featureCursor.NextFeature();
    while (feature != null)
    {
        activeView.Extent = feature.Shape.Envelope;
        activeView.Refresh();
        feature = featureCursor.NextFeature();
    }
}

private void btnMeasure_Click(object sender, EventArgs e)
{
    IMap map = axMapControl1.Map;
    IActiveView activeView = map as IActiveView;
    IMapUnits mapUnits = map.MapUnits;
    IUnitConverter unitConverter = new UnitConverterClass();
    IPoint startPoint = activeView.ScreenDisplay.DisplayTransformation.ToMapPoint(
        (int)txtStartX.Value, (int)txtStartY.Value);
    IPoint endPoint = activeView.ScreenDisplay.DisplayTransformation.ToMapPoint(
        (int)txtEndX.Value, (int)txtEndY.Value);
    double distance = unitConverter.ConvertUnits(
        startPoint.DistanceTo(endPoint), mapUnits, esriUnits.esriKilometers);
    lblDistance.Text = string.Format("{0}千米", distance.ToString("F2"));
}

4. 实现空间插值功能

private void btnInterpolation_Click(object sender, EventArgs e)
{
    IMap map = axMapControl1.Map;
    IActiveView activeView = map as IActiveView;
    ILayer layer = map.get_Layer(0);
    IFeatureLayer featureLayer = layer as IFeatureLayer;
    IFeatureClass featureClass = featureLayer.FeatureClass;
    IFields fields = featureClass.Fields;
    IField field = fields.get_Field(1);
    IGeoDataset geoDataset = featureClass as IGeoDataset;
    IBasicRasterDataset basicRasterDataset = null;
    if (field.Type == esriFieldType.esriFieldTypeDouble)
    {
        IInterpolationOp interpolationOp = new RasterInterpolationOpClass();
        IGeoDataset outGeoDataset = null;
        if (cmbAlgorithm.SelectedIndex == 0)
        {
            outGeoDataset = interpolationOp.IDW(geoDataset, 2, 2, 1500, 0.5);
        }
        else if (cmbAlgorithm.SelectedIndex == 1)
        {
            outGeoDataset = interpolationOp.Kriging(geoDataset, 2, 2, 1500, 0.5, 0.1);
        }
        else if (cmbAlgorithm.SelectedIndex == 2)
        {
            IRbfFunction rbfFunction = new ThinPlateSplineFunctionClass();
            outGeoDataset = interpolationOp.RBF(geoDataset, 2, 2, 1500, 0.5, rbfFunction);
        }
        basicRasterDataset = outGeoDataset as IBasicRasterDataset;
    }
    else
    {
        MessageBox.Show("所选字段不是数值类型！");
    }
    if (basicRasterDataset != null)
    {
        IRasterLayer rasterLayer = new RasterLayerClass();
        rasterLayer.CreateFromDataset(basicRasterDataset);
        map.AddLayer(rasterLayer);
        activeView.Extent = rasterLayer.AreaOfInterest;
        activeView.Refresh();
    }
}

5. 实现工具可扩展功能

public interface IMyTool
{
    string Name { get; }
    void OnClick();
}

public class MyTool1 : IMyTool
{
    public string Name => "工具1";
    public void OnClick()
    {
        MessageBox.Show("工具1被点击！");
    }
}

public class MyTool2 : IMyTool
{
    public string Name => "工具2";
    public void OnClick()
    {
        MessageBox.Show("工具2被点击！");
    }
}

public partial class Form1 : Form
{
    private AxMapControl axMapControl1;
    private Dictionary<string, IMyTool> tools = new Dictionary<string, IMyTool>();
    public Form1()
    {
        InitializeComponent();
        this.axMapControl1 = new AxMapControl();
        this.axMapControl1.Dock = DockStyle.Fill;
        this.Controls.Add(this.axMapControl1);
        InitTools();
    }
    private void InitTools()
    {
        tools.Add("工具1", new MyTool1());
        tools.Add("工具2", new MyTool2());
        foreach (var tool in tools)
        {
            ToolStripMenuItem menuItem = new ToolStripMenuItem(tool.Key);
            menuItem.Click += MenuItem_Click;
            contextMenuStrip1.Items.Add(menuItem);
        }
    }
    private void MenuItem_Click(object sender, EventArgs e)
    {
        ToolStripMenuItem menuItem = sender as ToolStripMenuItem;
        IMyTool tool = tools[menuItem.Text];
        tool.OnClick();
    }
    private void btnTools_Click(object sender, EventArgs e)
    {
        contextMenuStrip1.Show(btnTools, new Point(0, btnTools.Height));
    }
}