C# 在SHARPMAP中创建新图层
我正在制作sharpmaps,比如说我有一张我们的地图,如何在地图上添加新的图层 因为我需要在基本层上写下州名,并用不同的颜色给每个州涂上颜色。C# 在SHARPMAP中创建新图层,c#,maps,sharpmap,C#,Maps,Sharpmap,我正在制作sharpmaps,比如说我有一张我们的地图,如何在地图上添加新的图层 因为我需要在基本层上写下州名,并用不同的颜色给每个州涂上颜色。 在Sharpmaps中有可能实现这个目标吗?我认为在Sharpmaps中不可能 然而,在c#中,它可以通过映射州边界的坐标来实现。必须对每个州使用“自定义颜色”,对州名称使用“标签层” 您必须首先定义一个委托方法。该委托将FeatureDataRow作为参数,您可以处理自定义样式 比如说 private SharpMap.Styles.VectorSt
在Sharpmaps中有可能实现这个目标吗?我认为在Sharpmaps中不可能 然而,在c#中,它可以通过映射州边界的坐标来实现。必须对每个州使用“自定义颜色”,对州名称使用“标签层” 您必须首先定义一个委托方法。该委托将FeatureDataRow作为参数,您可以处理自定义样式 比如说
private SharpMap.Styles.VectorStyle GetCountryStyle(SharpMap.Data.FeatureDataRow row)
{
SharpMap.Styles.VectorStyle style = new SharpMap.Styles.VectorStyle();
switch (row["NAME"].ToString().ToLower())
{
case "denmark": //If country name is Danmark, fill it with green
style.Fill = Brushes.Green;
return style;
case "united states": //If country name is USA, fill it with Blue and add a red outline
style.Fill = Brushes.Blue;
style.Outline = Pens.Red;
return style;
case "china": //If country name is China, fill it with red
style.Fill = Brushes.Red;
return style;
default:
break;
}
//If country name starts with S make it yellow
if (row["NAME"].ToString().StartsWith("S"))
{
style.Fill = Brushes.Yellow;
return style;
}
// If geometry is a (multi)polygon and the area of the polygon is less than 30, make it cyan
else if (row.Geometry is GeoAPI.Geometries.IPolygonal && row.Geometry.Area < 30)
{
style.Fill = Brushes.Cyan;
return style;
}
else //None of the above -> Use the default style
return null;
}
对于标签层,您必须将新层定义为LabelLayer
比如说
//Name of table in database
string tablename = "Roads";
//Name of object ID column - MUST be integer!
string idColumn = "gid";
//Create layer
SharpMap.Layers.VectorLayer layRoads= new SharpMap.Layers.VectorLayer("Roads");
layRoads.DataSource = datasource;
//Set up a road label layer
SharpMap.Layers.LabelLayer layRoadLabel = new SharpMap.Layers.LabelLayer("Road labels");
//Set the datasource to that of layRoads.
layRoadLabel.DataSource = layRoads.DataSource;
layRoadLabel.Enabled = true;
//Specifiy field that contains the label string.
layRoadLabel.LabelColumn = "RoadOfName";
//Add layer to map
myMap.Layers.Add(layRoads);
//Add label layer to map
myMap.Layers.Add(layRoadLabel);
告诉所有人我认为这个链接有帮助
//Name of table in database
string tablename = "Roads";
//Name of object ID column - MUST be integer!
string idColumn = "gid";
//Create layer
SharpMap.Layers.VectorLayer layRoads= new SharpMap.Layers.VectorLayer("Roads");
layRoads.DataSource = datasource;
//Set up a road label layer
SharpMap.Layers.LabelLayer layRoadLabel = new SharpMap.Layers.LabelLayer("Road labels");
//Set the datasource to that of layRoads.
layRoadLabel.DataSource = layRoads.DataSource;
layRoadLabel.Enabled = true;
//Specifiy field that contains the label string.
layRoadLabel.LabelColumn = "RoadOfName";
//Add layer to map
myMap.Layers.Add(layRoads);
//Add label layer to map
myMap.Layers.Add(layRoadLabel);