目录

效果

代码

代码分析

加载模式

---

效果

代码

#include "stdafx.h"
#include <osg/Notify>
#include <osgGA/StateSetManipulator>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>#include <osgEarth/MapNode>
#include <osgEarth/ImageLayer>
#include <osgEarth/ModelLayer>
#include <osgEarthUtil/ExampleResources>
#include <osgEarthUtil/EarthManipulator>#include <osgEarthSymbology/Style>
#include <osgEarthFeatures/FeatureModelLayer>#include <osgEarthDrivers/gdal/GDALOptions>
#include <osgEarthDrivers/feature_ogr/OGRFeatureOptions>
#include <osgEarthDrivers/agglite/AGGLiteOptions>using namespace osgEarth;
using namespace osgEarth::Features;
using namespace osgEarth::Drivers;
using namespace osgEarth::Symbology;
using namespace osgEarth::Util;int usage(const std::string& app)
{OE_NOTICE "\n" << app << "\n"	// 绘制特征的方法<< "  --rasterize           : draw features as rasterized image tiles \n" // 光栅化平铺瓦片图<< "  --drape               : draw features as projected texture \n"	// 投影纹理<< "  --clamp               : draw features using shader clamping \n"	// 使用贴地着色器<< "  --mem                 : load features from memory \n"				// 加载默认线<< "  --labels              : add feature labels \n"					// 添加文本标签<< "\n"<< MapNodeHelper().usage()<< std::endl;return 0;
}//
// NOTE: run this sample from the repo/tests directory.
//
int main(int argc, char** argv)
{osg::ArgumentParser arguments(&argc, argv);if (arguments.read("--help"))return usage(argv[0]);// cmd执行命令时，输入： osgearth_featuresd.exe --rasterize --mem --labels --drape --clamp (一些参数)// 当输入了某个参数，则获取到的值为1，否则为0/*bool useRaster = arguments.read("--rasterize");bool useMem = arguments.read("--mem");bool useLabels = arguments.read("--labels");bool useDraping = arguments.read("--drape");bool useClamping = arguments.read("--clamp");*/bool useRaster = true;bool useMem = true;bool useLabels = true;bool useDraping = true;bool useClamping = true;std::cout << useRaster << useMem << useLabels << useDraping << useClamping << std::endl;osgViewer::Viewer viewer(arguments);// Start by creating the map:Map* map = new Map();// Start with a basemap imagery layer; we'll be using the GDAL driver// to load a local GeoTIFF file:// 添加默认地图GDALOptions basemap;// GDAL选项类，继承自TileSourceOptionsbasemap.url() = "../data/world.tif";map->addLayer(new ImageLayer(ImageLayerOptions("basemap", basemap)));// Next we add a feature layer. // 添加shp文件OGRFeatureOptions featureData;if (!useMem){// Configures the feature driver to load the vectors from a shapefile:// 如果给出相对路径，则国界线总是加载不上// 此处必须给全路径！！！featureData.url() = "F:\\point-cloud-lab-new\\PointCloudLab\\GeoEngine_output\\data\\world.shp";std::cout << "add world.shp" << std::endl;}else{// the --mem options tells us to just make an in-memory geometry:// 当没有 --mem参数时，采用默认的line绘制Ring* line = new Ring();line->push_back(osg::Vec3d(60, 20, 0));line->push_back(osg::Vec3d(120, 20, 0));line->push_back(osg::Vec3d(120, 60, 0));line->push_back(osg::Vec3d(60, 60, 0));featureData.geometry() = line;std::cout << "don't add world.shp" << std::endl;}// Make a feature source layer and add it to the Map:// 制作特征源图层并添加到mapFeatureSourceLayerOptions ogrLayer;ogrLayer.name() = "vector-data";// 矢量数据ogrLayer.featureSource() = featureData;// shp 文件或者默认linemap->addLayer(new FeatureSourceLayer(ogrLayer));// Define a style for the feature data. Since we are going to render the// vectors as lines, configure the line symbolizer:// 设置矢量面样式（包括边界线）Style style;LineSymbol* ls = style.getOrCreateSymbol<LineSymbol>();ls->stroke()->color() = Color::Yellow;ls->stroke()->width() = 2.0f;// 可以将线宽设置宽一些，更容易看出不同参数useDraping和useClamping产生的区别ls->tessellationSize()->set(100, Units::KILOMETERS);// 细分程度if (useDraping)//是否设置drape属性{AltitudeSymbol* alt = style.getOrCreate<AltitudeSymbol>();alt->clamping() = alt->CLAMP_TO_TERRAIN;alt->technique() = alt->TECHNIQUE_DRAPE;std::cout << "drape" << std::endl;}else if (useClamping)// 贴地属性{AltitudeSymbol* alt = style.getOrCreate<AltitudeSymbol>();alt->clamping() = alt->CLAMP_TO_TERRAIN;alt->technique() = alt->TECHNIQUE_GPU;// 线的细分程度ls->tessellationSize()->set(100, Units::KILOMETERS);RenderSymbol* render = style.getOrCreate<RenderSymbol>();render->depthOffset()->enabled() = true;render->depthTest() = false;std::cout << "no drape,but clamp" << std::endl;}if (useRaster)// 光栅化{AGGLiteOptions rasterOptions;rasterOptions.featureOptions() = featureData;rasterOptions.styles() = new StyleSheet();rasterOptions.styles()->addStyle(style);map->addLayer(new ImageLayer("My Features", rasterOptions));std::cout << "raster" << std::endl;}else //if (useGeom){FeatureModelLayerOptions fml;fml.name() = "My Features";fml.featureSourceLayer() = "vector-data";fml.styles() = new StyleSheet();fml.styles()->addStyle(style);// fml.enableLighting() = false;map->addLayer(new FeatureModelLayer(fml));std::cout << "no raster" << std::endl;}if (useLabels && !useRaster)// 有标签且非光栅化{// set up symbology for drawing labels. We're pulling the label// text from the name attribute, and its draw priority from the// population attribute.// 设置文本样式Style labelStyle;TextSymbol* text = labelStyle.getOrCreateSymbol<TextSymbol>();text->content() = StringExpression("[cntry_name]");//如果需要显示汉字，则需要转换成UTF-8编码text->priority() = NumericExpression("[pop_cntry]");text->size() = 26.0f;// 字号有些大text->alignment() = TextSymbol::ALIGN_CENTER_CENTER;text->fill()->color() = Color::White;text->halo()->color() = Color::DarkGray;// 文字光环颜色// and configure a model layer:FeatureModelLayerOptions fml;fml.name() = "Labels";fml.featureSourceLayer() = "vector-data";fml.styles() = new StyleSheet();fml.styles()->addStyle(labelStyle);map->addLayer(new FeatureModelLayer(fml));std::cout << "no raster, but labels" << std::endl;}// That's it, the map is ready; now create a MapNode to render the Map:MapNode* mapNode = new MapNode(map);viewer.setSceneData(mapNode);viewer.setCameraManipulator(new EarthManipulator());// add some stock OSG handlers:MapNodeHelper().configureView(&viewer);return viewer.run();
}

代码分析

osgEarth表达矢量的基本思路是：

• 先将shp文件读取到矢量源图层FeatureSourceLayer中，
• 这个图层加载到osgEarth的图层列表中是不显示的，
• 必须得再加载一个专门的符号化图层，将其符号化，才能正常显示。

 
 
1. 先声明基础地图
osgEarth::Drivers::GDALOptions basemap;
basemap.url() = "world.tif";
// 添加影像图到map节点
map->addLayer( new ImageLayer(ImageLayerOptions("basemap", basemap)));
 
 
2. 加载特征数据
osgEarth::Drivers::OGRFeatureOptions featureData;
featureData.url() = "world.shp";
// 特征源图层选项设置
osgEarth::Features::FeatureSourceLayerOptions ogrLayer;
ogrLayer.name() = "vector-data";
ogrLayer.featureSource() = featureData;
map->addLayer(new osgEarth::Features::FeatureSourceLayer(ogrLayer));
 
/*******↑featureData添加到FeatureSourceLayer,*****↓符号化*******/
 
3.初始化线样式
// 对ls alt render 进行设置
Style style;
osgEarth::Symbology::LineSymbol* ls = style.getOrCreateSymbol<LineSymbol>();
osgEarth::Symbology::AltitudeSymbol* alt = style.getOrCreate<AltitudeSymbol>();
osgEarth::Symbology::RenderSymbol* render = style.getOrCreate<RenderSymbol>();
 
 
4.光栅化或矢量化，二选一
4.1光栅化
osgEarth::Drivers::AGGLiteOptions rasterOptions;
rasterOptions.featureOptions() = featureData;
rasterOptions.styles()->addStyle( style );
map->addLayer(new ImageLayer("My Features", rasterOptions) );
 
4.2矢量化
osgEarth::Features::FeatureModelLayerOptions fml;
fml.styles()->addStyle(style);
map->addLayer(new FeatureModelLayer(fml));
 
5.如果需要加入label样式，以矢量化为前提
osgEarth::Symbology::Style labelStyle;
osgEarth::Symbology::TextSymbol* text = labelStyle.getOrCreateSymbol<TextSymbol>();
FeatureModelLayerOptions fml;
fml.styles()->addStyle( labelStyle );
map->addLayer(new FeatureModelLayer(fml));

加载模式

// rasterize 光栅化，不输入时，会显示名称
// mem参数输入，加载矩形，否则加载world.shp文件。shp文件路径一定要写全路径，否则无法加载。
// labels 可以不用填写。
// clamp 和 drape 任选其一。// 采用clamp方式绘制
osgearth_featuresd.exe --rasterize --mem --labels --clamp// 采用drape方式绘制
osgearth_featuresd.exe --rasterize --mem --labels --drape// 还有多种组合方式
osgearth_featuresd.exe --labels --drape