public SelectResult SelectLine(GISVertex vertex, List <GISFeature> features,
GISView view, GISExtent MinSelectExtent)
{
Double distance = Double.MaxValue;
int id = -1;
for (int i = 0; i < features.Count; i++) //找最近的feature判断是否有效
{
if (MinSelectExtent.IntersectOrNot(features[i].spatialpart.extent) == false)
{
continue;
}
GISLine line = (GISLine)(features[i].spatialpart);
double dist = line.Distance(vertex);
//Console.WriteLine("dist:" + dist);
if (dist < distance)//每次找到最小的距离并记录id号
{
distance = dist;
id = i;
}
}
Console.WriteLine("id:" + id.ToString());//测试id是否存在
//Console.WriteLine(distance);
//精选
if (id == -1)//经过遍历 没有与minsextent相交的点则跳出
{
SelectedFeature = null;
return(SelectResult.TooFar);
}
else
{
double screendistance = view.ToScreenDistance(distance);
if (screendistance < GISConst.MinScreenDistance)
{
SelectedFeature = features[id];
return(SelectResult.OK);
}
else
{
SelectedFeature = null;
return(SelectResult.TooFar);//即使在粗选相交 精选距离也超过了限制 则返回
}
}
}
//输出图层所有GISFeatrue
static void WriteFeatures(GISLayer layer, BinaryWriter bw)
{
for (int featureindex = 0; featureindex < layer.FeatureCount(); featureindex++)
{
GISFeature feature = layer.GetFeature(featureindex);
if (layer.ShapeType == SHAPETYPE.point)
{
((GISPoint)feature.spatialpart).centroid.WriteVertex(bw);
}
else if (layer.ShapeType == SHAPETYPE.line)
{
GISLine line = (GISLine)(feature.spatialpart);
WriteMultipleVertexes(line.Vertexes, bw);
}
else if (layer.ShapeType == SHAPETYPE.polygon)
{
GISPolygon polygon = (GISPolygon)(feature.spatialpart);
WriteMultipleVertexes(polygon.Vertexes, bw);
}
WriteAttributes(feature.attributepart, bw);
}
}
