ArcEngine 专题图关键代码

最新推荐文章于 2022-04-19 17:11:12 发布

lovedigis

最新推荐文章于 2022-04-19 17:11:12 发布

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文章标签： ArcEngine 专题图制作唯一值

本文链接：https://blog.youkuaiyun.com/lovedigis/article/details/50130785

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该博客详细介绍了如何使用ArcEngine进行唯一值专题图的制作。通过获取图层上的要素，定义唯一值渲染器，设置渲染字段，创建并应用填充符号，以及对字段值进行排序和颜色分配，最终实现图层的渲染更新。

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一、类别

唯一值：

/// <summary>
/// 应用唯一值渲染面要素层
/// </summary>
/// <param name="pGeoFeaturelayer"></param>
private void ApplyUniqueValueRenderer2Polygon(IGeoFeatureLayer pGeoFeatureLayer)
{
IFeatureLayer pFeatureLayer = pGeoFeatureLayer as IFeatureLayer;

//获取图层上的feature
IFeatureClass pFeatureClass = pFeatureLayer.FeatureClass;

IFeatureCursor pFeatureCursor = pFeatureClass.Search(null, false);

//定义单值图渲染组件
IUniqueValueRenderer pUniqueValueRenderer = new UniqueValueRendererClass();

sRendererField = lbResultYearField.Items[0].ToString();
int fieldIndex = pFeatureClass.Fields.FindFieldByAliasName(sRendererField);
IField pField = pFeatureClass.Fields.get_Field(fieldIndex);

//设置渲染字段对象
pUniqueValueRenderer.FieldCount = 1;
pUniqueValueRenderer.set_Field(0, pField.Name);

//创建填充符号
ISimpleFillSymbol PFillSymbol = new SimpleFillSymbolClass();
pUniqueValueRenderer.DefaultSymbol = (ISymbol)PFillSymbol;
pUniqueValueRenderer.UseDefaultSymbol = false;

//QI the table from the geoFeatureLayer and get the field number of
//ITable pTable;
//int fieldNumber;
//pTable = pGeoFeatureLayer as ITable;
//fieldNumber = pTable.FindField("ID");
//if (fieldNumber == -1)
//{
// MessageBox.Show("Can't find field called ", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
//}

//为每个值设置一个符号
//int n = pFeatureClass.FeatureCount(null);
//for (int i = 0; i < n; i++)
//{
// IFeature pFeature = pFeatureCursor.NextFeature();
// IClone pSourceClone = PFillSymbol as IClone;
// ISimpleFillSymbol pSimpleFillSymbol = pSourceClone.Clone() as ISimpleFillSymbol;
// //string sFeatureValue = pFeature.get_Value(pFeature.Fields.FindField("ID")).ToString();
// string sFeatureValue = pFeature.get_Value(fieldIndex).ToString();
// pUniqueValueRenderer.AddValue(sFeatureValue, pField.AliasName, (ISymbol)pSimpleFillSymbol);
//}

//字段值排序(升序)
ITable pTable = pFeatureClass as ITable;
ITableSort pTableSort = new TableSortClass();
IQueryFilter pQueryFilter = new QueryFilterClass();
pQueryFilter.WhereClause = "";
pTableSort.Table = pTable;
pTableSort.QueryFilter = pQueryFilter;
pTableSort.Fields = pField.Name;
//pTableSort.set_SortCharacters(pField.Name);
pTableSort.set_Ascending(pField.Name, true);
pTableSort.Sort(null);

//为每个值设置一个符号
ICursor pCursor = pTableSort.Rows;
IRow pRow = pCursor.NextRow();
while (pRow != null)
{
IClone pSourceClone = PFillSymbol as IClone;
ISimpleFillSymbol pSimpleFillSymbol = pSourceClone.Clone() as ISimpleFillSymbol;
string sFeatureValue = pRow.get_Value(fieldIndex).ToString();
pUniqueValueRenderer.AddValue(sFeatureValue, pField.AliasName, (ISymbol)pSimpleFillSymbol);
pRow = pCursor.NextRow();
}

//创建并设置随机色谱
//IRandomColorRamp pColorRamp = new RandomColorRampClass();
//pColorRamp.StartHue = 0;
//pColorRamp.MinValue = 99;
//pColorRamp.MinSaturation = 15;
//pColorRamp.EndHue = 360;
//pColorRamp.MaxValue = 100;
//pColorRamp.MaxSaturation = 30;
//pColorRamp.Size = 100;

//Get the color ramp
IColorRamp pColorRamp = (IColorRamp)_pStyleGalleryItem.Item;
pColorRamp.Size = pUniqueValueRenderer.ValueCount;
bool ok = true;
pColorRamp.CreateRamp(out ok);
IEnumColors pEnumRamp;
pEnumRamp = pColorRamp.Colors;

//为每个符号设置颜色
for (int i = 0; i <= pUniqueValueRenderer.ValueCount - 1; i++)
{
string xv = pUniqueValueRenderer.get_Value(i);
if (xv != "")
{
ISimpleFillSymbol pNextSymbol = (ISimpleFillSymbol)pUniqueValueRenderer.get_Symbol(xv);
pNextSymbol.Color = pEnumRamp.Next();
pUniqueValueRenderer.set_Symbol(xv, (ISymbol)pNextSymbol);
}
}
//将单值图渲染对象与渲染图层挂钩
pGeoFeatureLayer.Renderer = (IFeatureRenderer)pUniqueValueRenderer;
//pGeoFeatureLayer.DisplayField = "ID";
pGeoFeatureLayer.DisplayField = pField.Name;
//刷新地图和TOOCotrol
_pMapControl.ActiveView.ContentsChanged();
_pMapControl.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGeography, pGeoFeatureLayer, null);
_pMapControl.Refresh();
}