AE中FeatureRender的图层渲染_igeofeaturelayerptr-优快云博客

本文链接：https://blog.youkuaiyun.com/PuttyTree/article/details/4316540

本文介绍如何使用ArcGIS API实现图层的唯一值渲染。通过创建随机颜色渐变并将其应用于图层的特定字段，可以为不同的值设置独特的颜色，从而在地图上清晰地区分不同的特征。

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类型一：AE：IUniqueValueRendererPtr 实现图层唯一值渲染

       IGeoFeatureLayerPtr pGeoFeaLyr;
        CString sFldName = _T("FWID");//列名
        IMapControl2Ptr pMapControl;
        pMapControl=m_MapCtrl.get_Object();

pGeoFeaLyr=pMapControl->GetLayer(0);//层索引
if(pGeoFeaLyr == NULL) return;

IQueryFilterPtr pFilter(__uuidof(QueryFilter));
IFeatureCursorPtr pFeaCur;

        IFeatureClassPtr pFeaCls;
        pGeoFeaLyr->get_FeatureClass(&pFeaCls);
        if( pFeaCls == NULL) return;

        pFeaCur = pFeaCls->Search(pFilter,FALSE);
        if(pFeaCur == NULL) return;

        IEnumColorsPtr pEnumColors;
        IRandomColorRampPtr pRanColor(__uuidof(RandomColorRamp));
        pRanColor->put_MinSaturation(20);
        pRanColor->put_MaxSaturation(40);
        pRanColor->put_MinValue(85);
        pRanColor->put_MaxValue(100);
        pRanColor->put_StartHue(76);
        pRanColor->put_EndHue(188);
        pRanColor->put_Size(100);
        VARIANT_BOOL bOk;
        pRanColor->CreateRamp(&bOk);
        if(!bOk) return;
        pRanColor->get_Colors(&pEnumColors);

        if(pEnumColors == NULL) return;


        IUniqueValueRendererPtr pUniRender(__uuidof(UniqueValueRenderer));
        pUniRender->put_FieldCount(1);
        pUniRender->put_Field(0,(_bstr_t)sFldName);

        IColorPtr pColor(__uuidof(RgbColor));
        pColor->put_RGB(RGB(255,0,0));

        ISimpleLineSymbolPtr pSimLineSym;
        pSimLineSym.CreateInstance(__uuidof(SimpleLineSymbol));
        pSimLineSym->put_Color(pColor);
        pSimLineSym->put_Width(0.8);
        pSimLineSym->put_Style(esriSLSDash);

IFeaturePtr pFeature = pFeaCur->NextFeature();

        while ( pFeature != NULL)
        {
            VARIANT var;
            pFeature->get_Value(2,&var);//列索引
            if(var.bstrVal == (BSTR)"") continue;
            long nValueCount;
            pUniRender->get_ValueCount(&nValueCount);

            IColorPtr pTmpColor;
            pTmpColor = pEnumColors->Next();
            OLE_COLOR rgb;
            pTmpColor->get_RGB(&rgb);
            if (pTmpColor == NULL)
            {
                pEnumColors->Reset();
                pTmpColor = pEnumColors->Next();
            }

            ISimpleFillSymbolPtr pSimFillSym(__uuidof(SimpleFillSymbol));
            ISymbolPtr pSymbol;
            pSimFillSym->put_Color(pTmpColor);
            pSimFillSym->PutOutline(pSimLineSym);

pSymbol=pSimFillSym;

            pUniRender->AddValue((_bstr_t)var,(_bstr_t)var,pSymbol);
            pUniRender->put_Label(_bstr_t("Parcels"));
            pFeature = pFeaCur->NextFeature();
        }

        IFeatureRendererPtr pFeaRender = (IFeatureRendererPtr)pUniRender;
        pGeoFeaLyr->putref_Renderer(pFeaRender);
        IActiveViewPtr pAV;
        pAV=pMapControl->GetActiveView();
        pAV->Refresh();