feature_model_scatter.earth

<!--
osgEarth Sample

Model Scattering using the "feature_geom" driver.

For each polygon in the feature geometry, scatter model instances within
that polygon as a specific density (instances/sqkm). Scattered placement
is randomized, but it is randomized exactly the same way each time.
-->

<map name="Demo: Model Scattering">

    <OGRFeatures name="trees-data">
        <url>../data/parks.shp</url>
        <build_spatial_index>true</build_spatial_index>
    </OGRFeatures>

    <FeatureModel name="trees" enabled="true">

        <!-- Feature Layer to read the data from -->
        <features> trees-data </features>

        <!-- The stylesheet will describe how to render the feature data. In this case
             we indicate model substitution with density-based scattering. The "density"
             units are instances-per-sqkm. -->

        <layout>
            <crop_features>true</crop_features>
            <level max_range="25000" style="park-polygons"/>
            <level max_range="7000"  style="parks-1"/>
            <level max_range="3000"  style="parks-2"/>
            <level max_range="1000"  style="parks-3"/>
        </layout>

        <styles>
            <style type="text/css">
                park-polygons {
                   fill:                #00ff007f;
                   altitude-clamping:   terrain-drape;
                }    
                parks {
                   model:               "../data/tree.osg";
                   model-placement:     random;
                   altitude-clamping:   terrain;
                   altitude-resolution: 0.001;
                   render-transparent:  true;
                   render-min-alpha:    0.15;                   
                }
                parks-1 : parks {
                   model-density:     1000;
                   model-scale:       2.0;
                   model-random-seed: 0;
                }            
                parks-2 : parks {
                   model-density:     2500;
                   model-scale:       2.5;
                   model-random-seed: 1;
                }              
                parks-3 : parks {
                   model-density:     5000;
                   model-scale:       2.25;
                   model-random-seed: 2;
                }                
            </style>
        </styles>        
    </FeatureModel>

    <xi:include href="readymap_imagery.xml"/>
    <xi:include href="readymap_elevation.xml"/>

    <Viewpoints home="0">
        <viewpoint name="DC Overview">
            <heading>-3.69224e-08</heading>
            <pitch>-89.9</pitch>
            <range>22073.3m</range>
            <long>-77.02170005868915</long>
            <lat>38.90150049600116</lat>
            <height>-12.07075788639486</height>
            <srs>+proj=longlat +datum=WGS84 +no_defs </srs>
        </viewpoint>
        <viewpoint name="DC close up" heading="-13.48" lat="38.911" long="-77.051" pitch="-10.1" range="2711"/>
    </Viewpoints>

</map>