C#中GDAL读写shp图层
目录
采用GDAL17的C#库进行shp图层属性表读取和修改操作，C#DLL库解压后包含文件如下：
添加引用主要是带csharp的gdal、ogr、osr三个DLL，程序代码如下
using OSGeo.OGR;
using OSGeo.OSR;
using OSGeo.GDAL;读取shp图层操作
public void Reforming(string shpFilePath)
{
Gdal.SetConfigOption("GDAL_FILENAME_IS_UTF8", "NO");
Gdal.SetConfigOption("SHAPE_ENCODING", "");
Ogr.RegisterAll();// 注册所有的驱动
DataSource ds = Ogr.Open(shpFilePath, 1);//0表示只读，1表示可修改
if (ds == null) { MessageBox.Show("打开文件【{0}】失败！", shpFilePath); return; }
// 获取第一个图层
int iLayerCount = ds.GetLayerCount();
Layer oLayer = ds.GetLayerByIndex(0);
if (oLayer == null) { MessageBox.Show("获取第{0}个图层失败！ n", "0"); return; }
fieldList = GetFieldList(oLayer);//获取图层属性表字段列表
int featureCount = oLayer.GetFeatureCount(0);
//B1.判断字段是否存在
#region shp属性表
{
if (!fieldList.Contains("LL_YAW"))
{
FieldDefn oFieldYaw = new FieldDefn("LL_YAW", FieldType.OFTReal);
oFieldYaw.SetWidth(10);
oFieldYaw.SetPrecision(8);
oLayer.CreateField(oFieldYaw, 1);
}
if (!fieldList.Contains("LL_ScaleX"))
{
FieldDefn oFieldYaw = new FieldDefn("LL_ScaleX", FieldType.OFTReal);
oFieldYaw.SetWidth(10);
oFieldYaw.SetPrecision(8);
oLayer.CreateField(oFieldYaw, 1);
}
if (!fieldList.Contains("LL_ScaleY"))
{
FieldDefn oFieldYaw = new FieldDefn("LL_ScaleY", FieldType.OFTReal);
oFieldYaw.SetWidth(10);
oFieldYaw.SetPrecision(8);
oLayer.CreateField(oFieldYaw, 1);
}
}
#endregion
//输出属性表字段的详细信息，数据类型、宽度、精度等
FeatureDefn oDefn1 = oLayer.GetLayerDefn();
int FieldCount1 = oDefn1.GetFieldCount();
string headerInfo = string.Empty;
{
for (int i = 0; i < FieldCount1; i++)
{
FieldDefn oField = oDefn.GetFieldDefn(i);
headerInfo += String.Format("{0}:{1} {2} {3}", oField.GetNameRef(), oField.GetFieldTypeName(oField.GetFieldType()), oField.GetWidth(), oField.GetPrecision());
headerInfo += Environment.NewLine;
}
}
MessageBox.Show(headerInfo);
Feature oFeature = null;
while ((oFeature = oLayer.GetNextFeature()) != null)
{
string name = oFeature.GetFieldAsString(0);
double x = oFeature.GetFieldAsDouble(1);
double y = oFeature.GetFieldAsDouble(2);
double z = oFeature.GetFieldAsDouble(3);
//B3.给新增加的字段赋值
oFeature.SetField(7, x);
oFeature.SetField(8, y);
oFeature.SetField(9, z);
oLayer.SetFeature(oFeature);//保存记录
}
oLayer.Dispose();
ds.Dispose();//关闭数据集
}
private List<string> GetFieldList(Layer mLayer)
{
List<string> newFieldList = new List<string>();
FeatureDefn oDefn = mLayer.GetLayerDefn();
int FieldCount = oDefn.GetFieldCount();
for (int i = 0; i < FieldCount; i++)
{
FieldDefn oField = oDefn.GetFieldDefn(i);
string fieldName = oField.GetNameRef();
newFieldList.Add(fieldName);
}
return newFieldList;
}
}
需要创建或获取shp图层的Spatial Reference空间参考坐标系WKT时，代码如下：
OSGeo.OSR.SpatialReference siref = oLayer.GetSpatialRef(); siref.ExportToWkt(out layerCSWKT); siref.ImportFromWkt(ref layerCSWKT);
2.创建shp图层，并将点的坐标值写入属性表代码如下：
private void button2_Click(object sender, EventArgs e)
{
OSGeo.GDAL.Gdal.SetConfigOption("GDAL_FILENAME_IS_UTF8", "NO");
// 为了使属性表字段支持中文，请添加下面这句
OSGeo.GDAL.Gdal.SetConfigOption("SHAPE_ENCODING", "");
string strVectorFile1 = @"C:\Users\DZY\Desktop\test6";
Ogr.RegisterAll();
string strDriver = "ESRI Shapefile";
Driver oDriver = Ogr.GetDriverByName(strDriver);
if (oDriver == null)
{
MessageBox.Show(" 驱动不可用！\n", strVectorFile1);
return;
}
DataSource ds1 = oDriver.CreateDataSource(strVectorFile1,null);
if (ds1 == null)
{
MessageBox.Show("创建矢量文件【%s】失败！\n", strVectorFile1);
return;
}
string wkt = "…";//自定义投影坐标系的WKT
OSGeo.OSR.SpatialReference sr = new OSGeo.OSR.SpatialReference(wkt);
Layer olayer1 = ds1.CreateLayer("PointLayer",sr,wkbGeometryType.wkbPoint,null);
//接下来创建属性表字段
// 先创建一个叫FieldID的整型属性
FieldDefn oFieldID = new FieldDefn("FieldID", FieldType.OFTInteger);
olayer1.CreateField(oFieldID, 1);
// 再创建一个叫FeatureName的字符型属性，字符长度为50
FieldDefn oFieldName = new FieldDefn("FieldName", FieldType.OFTString);
oFieldName.SetWidth(50);
olayer1.CreateField(oFieldName, 1);
//创建x坐标字段
FieldDefn oFieldX = new FieldDefn("x", FieldType.OFTReal);
oFieldX.SetWidth(10);
oFieldX.SetPrecision(8);
olayer1.CreateField(oFieldX, 1);
//创建y坐标字段
FieldDefn oFieldY = new FieldDefn("y", FieldType.OFTReal);
oFieldY.SetWidth(10);
oFieldY.SetPrecision(8);
olayer1.CreateField(oFieldY, 1);
//创建z坐标字段
FieldDefn oFieldZ= new FieldDefn("z", FieldType.OFTReal);
oFieldZ.SetWidth(10);
oFieldZ.SetPrecision(8);
olayer1.CreateField(oFieldZ, 1);
//写入第一条数据
FeatureDefn oDefn = olayer1.GetLayerDefn();
Feature oFeature = new Feature(oDefn);
oFeature.SetField(0, 0);
oFeature.SetField(1, "Point1");
oFeature.SetField(2, 489592.624);
oFeature.SetField(3, 3804367.891);
oFeature.SetField(4, 386.3);
Geometry geoPoint = new Geometry(OSGeo.OGR.wkbGeometryType.wkbPoint);
geoPoint.AddPoint(489592.624, 3804367.891, 386.3);
oFeature.SetGeometry(geoPoint);
olayer1.CreateFeature(oFeature);
//写入第二条数据
Feature oFeature1 = new Feature(oDefn);
oFeature1.SetField(0, 1);
oFeature1.SetField(1, "Point2");
oFeature1.SetField(2, 489602.624);
oFeature1.SetField(3, 3804367.891);
oFeature1.SetField(4, 389.3);
geoPoint.AddPoint(489602.624, 3804367.891, 389.3);
oFeature1.SetGeometry(geoPoint);
olayer1.CreateFeature(oFeature1);
oFeature1.Dispose();
olayer1.Dispose();
ds1.Dispose();
MessageBox.Show("shp图层创建完成！");
}
3.ArcMap中加载效果如下：多个点可采取循环遍历的方式实现。
