Geotools:将不同样式的点添加到同一地图图层
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【中文标题】Geotools:将不同样式的点添加到同一地图图层【英文标题】:Geotools: Add points with different styles to same map layer 【发布时间】:2016-06-18 23:14:04 【问题描述】:我在我的 java 项目中使用GeoTools 将不同大小、颜色和不透明度的点绘制到地图中。 由于它们有很多不同的样式,我最终在我的地图中添加了 数千层。目前每个添加的点都有自己的图层,因为我没有设法将它们添加到一个图层中。
我从我的 Entity 对象中获得分数。来自同一实体的每个点都具有相同的颜色。有更多具有相同名称/颜色的实体。
这是在地图上绘制一个实体的方式:
点的大小在下面的代码sn-p中动态计算:
public class ***
private final MapContent mapContent;
public ***()
this.mapContent = new MapContent();
public void addPoints(final HashMap<String, Color> colorsForEntities, final List<Entity> toDraw)
final GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();
// Create SimpleFeatureType for Point
final SimpleFeatureTypeBuilder pointTb = new SimpleFeatureTypeBuilder();
pointTb.setName("points");
pointTb.setCRS(DefaultGeographicCRS.WGS84);
pointTb.add("point", Point.class);
final SimpleFeatureBuilder pointFeatureBuilder = new SimpleFeatureBuilder(pointTb.buildFeatureType());
for (final Entity entity : toDraw)
final List<Point2D> pathPoints = entity.getPoints();
Color color = colorsForEntities.get(entity.getName());
Layer layerPoints;
Style pointStyle;
final float maxOpacity = MyProperties.getFloat(Constants.POINT_STYLE_OPACITY);
final float maxSize = MyProperties.getFloat(Constants.POINT_STYLE_SIZE);
final int NumPoints = pathPoints.size();
float opacity = maxOpacity;
float size = maxSize;
final float deltaOpacity = maxOpacity / NumPoints;
final float deltaSize = maxSize / NumPoints;
for (final Point2D point2D : pathPoints)
final Point point = geometryFactory.createPoint(new Coordinate(point2D.getX(), point2D.getY()));
pointFeatureBuilder.add(point);
final SimpleFeature feature = pointFeatureBuilder.buildFeature(null);
final DefaultFeatureCollection pointCollection = new DefaultFeatureCollection();
pointCollection.add(feature);
pointStyle = SLD.createPointStyle("Circle", color, color, opacity, size);
opacity = opacity - deltaOpacity;
size = size - deltaSize;
layerPoints = new FeatureLayer(pointCollection, pointStyle);
mapContent.addLayer(layerPoints);
是否可以将点添加到单个图层或至少获得更少的图层?
【问题讨论】:
【参考方案1】:它可以更有效地完成:-) 我认为最简单的方法是从entity
s 构建您的SimpleFeature
s,以便它们包含所需的颜色、大小和不透明度。比如:
final SimpleFeatureTypeBuilder pointTb = new SimpleFeatureTypeBuilder();
pointTb.setName("points");
pointTb.setCRS(DefaultGeographicCRS.WGS84);
pointTb.add("point", Point.class);
pointTb.add("color", String.class);
pointTb.add("size", Integer.class);
pointTb.add("opacity", Float.class);
final SimpleFeatureBuilder pointFeatureBuilder = new SimpleFeatureBuilder(pointTb.buildFeatureType());
然后您可以创建一个Style
,它采用这些属性并使用它们来设置每个点的样式。类似(未经测试):
StyleBuilder sb = new StyleBuilder();
FilterFactory2 ff = sb.getFilterFactory();
Mark testMark = sb.createMark(sb.literalExpression("Circle"),
sb.createFill(sb.attributeExpression("color"),sb.attributeExpression("opacity")),
null);
Graphic graph = sb.createGraphic(null, // An external graphics if needed
new Mark[] testMark , // a Mark if not an external graphics
null, // aSymbol
ff.literal(sb.attributeExpression("opacity")), // opacity
ff.property("size"), // read from feature "size" attribute
ff.literal(0)); // rotation, here read into the feature
PointSymbolizer aPointSymbolizer = sb.createPointSymbolizer(graph);
// creation of the style
org.geotools.styling.Style style = sb.createStyle(aPointSymbolizer);
由于 SLD 不提供对循环的任何支持,我认为没有任何方法可以避免将每个 entity
分解为具有自己样式的一组单独的点,除非你想写一个 @ 987654321@.
【讨论】:
链接失效。我们可以在不重新加载地图的情况下将样式应用于地图吗?以上是关于Geotools:将不同样式的点添加到同一地图图层的主要内容,如果未能解决你的问题,请参考以下文章