sharpmap中添加自定义图层

最新推荐文章于 2025-10-26 14:18:33 发布

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本文介绍了一种在地图上绘制风矢图层的方法。通过创建一个名为WindArrow的VectorLayer，并使用自定义主题来设置样式。针对每个特征数据行生成一个特定大小的位图作为风矢符号。

        //'增加风矢图层
        SharpMap.Layers.VectorLayer windarrowLayer = new SharpMap.Layers.VectorLayer("Wind Arrow");
        windarrowLayer.DataSource = (map.Layers[3] as SharpMap.Layers.VectorLayer).DataSource;
        windarrowLayer.Style.SymbolScale = 0.8F;
        windarrowLayer.SRID = 4326;
        windarrowLayer.MaxVisible = 15;
        SharpMap.Rendering.Thematics.CustomTheme iTheme = new SharpMap.Rendering.Thematics.CustomTheme(GetWindArrowStyle);
        windarrowLayer.Theme = iTheme;
        map.Layers.Add(windarrowLayer);

private static SharpMap.Styles.VectorStyle GetWindArrowStyle(SharpMap.Data.FeatureDataRow row)
{

        SharpMap.Styles.VectorStyle s = new SharpMap.Styles.VectorStyle();
        s.Fill = new SolidBrush(Color.Green);
        s.Symbol = GetWindArrow(row);
        return s;
    }

private static Bitmap GetWindArrow(SharpMap.Data.FeatureDataRow row)
{

        // Replace polygon with a center point (this is where we place the symbol
        row.Geometry = GeometryFactory.CreatePoint(
                                    row.Geometry.EnvelopeInternal.Centre.X,
                                    row.Geometry.EnvelopeInternal.Centre.Y);

        Random Rand = new Random();
        int size = 50;
        Bitmap b = new Bitmap(size, size);
        Graphics g = Graphics.FromImage(b);

        wmplot.clsWindArrow. CHyAwsView(g, new Point(25, 25), 10, 90);
        g.Dispose();
        return b;

}