/// <summary>
/// Extract sub-area of dfsu (2D) file to a new dfsu file
/// </summary>
/// <param name="sourceFilename">Name of source file, i.e. OresundHD.dfsu test file</param>
/// <param name="outputFilename">Name of output file</param>
/// <param name="x1">Lower left x coordinate of sub area</param>
/// <param name="y1">Lower left y coordinate of sub area</param>
/// <param name="x2">upper right x coordinate of sub area</param>
/// <param name="y2">upper right y coordinate of sub area</param>
public static void ExtractSubareaDfsu2D(string sourceFilename, string outputFilename, double x1, double y1, double x2, double y2)
{
DfsuFile dfsu = DfsFileFactory.DfsuFileOpen(sourceFilename);
// Node coordinates
double[] X = dfsu.X;
double[] Y = dfsu.Y;
float[] Z = dfsu.Z;
int[] Code = dfsu.Code;
// Loop over all elements, and all its nodes: If one node is inside
// region, element (and nodes) are to be included in new mesh
List <int> elmtsIncluded = new List <int>();
bool[] nodesIncluded = new bool[dfsu.NumberOfNodes];
for (int i = 0; i < dfsu.NumberOfElements; i++)
{
// Nodes of element
int[] nodes = dfsu.ElementTable[i];
// Check if one of the nodes of the element is inside region
bool elmtIncluded = false;
for (int j = 0; j < nodes.Length; j++)
{
int node = nodes[j] - 1;
if (x1 <= X[node] && X[node] <= x2 && y1 <= Y[node] && Y[node] <= y2)
{
elmtIncluded = true;
}
}
if (elmtIncluded)
{
// Add element to list of included elements
elmtsIncluded.Add(i);
// Mark all nodes of element as included
for (int j = 0; j < nodes.Length; j++)
{
int node = nodes[j] - 1;
nodesIncluded[node] = true;
}
}
}
// array containing numbers of existing nodes in new mesh (indices)
int[] renumber = new int[dfsu.NumberOfNodes];
// new mesh nodes
List <double> X2 = new List <double>();
List <double> Y2 = new List <double>();
List <float> Z2 = new List <float>();
List <int> Code2 = new List <int>();
List <int> nodeIds = new List <int>();
int i2 = 0;
for (int i = 0; i < dfsu.NumberOfNodes; i++)
{
if (nodesIncluded[i])
{
X2.Add(X[i]);
Y2.Add(Y[i]);
Z2.Add(Z[i]);
Code2.Add(Code[i]);
nodeIds.Add(dfsu.NodeIds[i]);
// Node with index i will get index i2 in new mesh
renumber[i] = i2;
i2++;
}
}
// New mesh elements
List <int[]> elmttable2 = new List <int[]>();
List <int> elmtIds = new List <int>();
for (int i = 0; i < elmtsIncluded.Count; i++)
{
// Add new element
int elmt = elmtsIncluded[i];
int[] nodes = dfsu.ElementTable[elmt];
// newNodes must be renumbered
int[] newNodes = new int[nodes.Length];
for (int j = 0; j < nodes.Length; j++)
{
// Do the renumbering of nodes from existing mesh to new mesh
newNodes[j] = renumber[nodes[j] - 1] + 1;
}
elmttable2.Add(newNodes);
elmtIds.Add(dfsu.ElementIds[i]);
}
// Create 2D dfsu file
DfsuBuilder builder = DfsuBuilder.Create(DfsuFileType.Dfsu2D);
// Setup header and geometry
builder.SetNodes(X2.ToArray(), Y2.ToArray(), Z2.ToArray(), Code2.ToArray());
//builder.SetNodeIds(nodeIds.ToArray());
builder.SetElements(elmttable2.ToArray());
builder.SetElementIds(elmtIds.ToArray()); // retain original element id's
builder.SetProjection(dfsu.Projection);
builder.SetTimeInfo(dfsu.StartDateTime, dfsu.TimeStepInSeconds);
if (dfsu.ZUnit == eumUnit.eumUUnitUndefined)
{
builder.SetZUnit(eumUnit.eumUmeter);
}
else
{
builder.SetZUnit(dfsu.ZUnit);
}
// Add dynamic items, copying from source
for (int i = 0; i < dfsu.ItemInfo.Count; i++)
{
IDfsSimpleDynamicItemInfo itemInfo = dfsu.ItemInfo[i];
builder.AddDynamicItem(itemInfo.Name, itemInfo.Quantity);
}
// Create new file
DfsuFile dfsuOut = builder.CreateFile(outputFilename);
// Add new data
float[] data2 = new float[elmtsIncluded.Count];
for (int i = 0; i < dfsu.NumberOfTimeSteps; i++)
{
for (int j = 0; j < dfsu.ItemInfo.Count; j++)
{
// Read data from existing dfsu
IDfsItemData <float> itemData = (IDfsItemData <float>)dfsu.ReadItemTimeStep(j + 1, i);
// Extract value for elements in new mesh
for (int k = 0; k < elmtsIncluded.Count; k++)
{
data2[k] = itemData.Data[elmtsIncluded[k]];
}
// write data
dfsuOut.WriteItemTimeStepNext(itemData.Time, data2);
}
}
dfsuOut.Close();
dfsu.Close();
}