public static double GetHeightFromCsv(this GtxFile gtxFile, string filePath, double latitude, double longitude)
{
StringReader stringReader = new StringReader(File.Open(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite).ToString());
string[] separators = { "," };
double nullReturnValue = -88.8888;
//Read first line (column headers/latitude)
string columnHeader = stringReader.ReadLine();
//Split column headers, convert to double[]
double[] columnHeaderValues = Array.ConvertAll(columnHeader.Split(separators, StringSplitOptions.RemoveEmptyEntries), Double.Parse);
//Check if latitude is in range; calculate column index
bool inRange = (longitude >= columnHeaderValues[0] && longitude <= columnHeaderValues[columnHeaderValues.Length]);
if (!inRange)
{
return(nullReturnValue);
}
int valueColumnIndex = (int)((longitude - columnHeaderValues[0]) / gtxFile.DeltaLatitudeDecimalDegrees);
double nearestColumnValue = columnHeaderValues[0] + (valueColumnIndex * gtxFile.DeltaLatitudeDecimalDegrees);
//Get second row; split, covert to double[]; get header value
string rowString = stringReader.ReadLine();
double[] rowValues = Array.ConvertAll(rowString.Split(separators, StringSplitOptions.None), Double.Parse);
double rowHeaderValue = rowValues[0];
//Check if longitude value is potentially in the range
inRange = (latitude >= rowHeaderValue);
if (!inRange)
{
return(nullReturnValue);
}
//calculate index value for matching row header value
int valueRowIndex = (int)((latitude - rowValues[0]) / gtxFile.DeltaLongitudeDecimalDegrees);
double nearestRowValue = rowValues[0] + (valueRowIndex * gtxFile.DeltaLongitudeDecimalDegrees);
//get to row with value
for (int i = 0; i < valueRowIndex; i++)
{
rowString = stringReader.ReadLine();
}
//Split row, convert to double[]; get height value; return value
rowValues = Array.ConvertAll(rowString.Split(separators, StringSplitOptions.None), Double.Parse);
double heightValue = rowValues[valueColumnIndex + 1];
return(heightValue);
}
public static void ToCsv(this GtxFile gtxFile, string filePath)
{
using (var streamWriter = new StreamWriter(filePath))
{
//very first entry is null
//first row = longitudes
for (int i = 0; i < gtxFile.NumberOfColumns; i++)
{
streamWriter.Write(",");
streamWriter.Write(gtxFile.LowerLeftLongitudeDecimalDegrees + (i * gtxFile.DeltaLongitudeDecimalDegrees));
}
//next row
streamWriter.WriteLine();
//height counter
int nh = 0;
//iterate through all rows/latitude
for (int i = 0; i < gtxFile.NumberOfRows; i++)
{
//first column = latitude
streamWriter.Write(gtxFile.LowerLeftLatitudeDecimalDegrees + (i * gtxFile.DeltaLatitudeDecimalDegrees));
//iterate through all columns/latitude
for (int j = 0; j < gtxFile.NumberOfColumns; j++)
{
streamWriter.Write(",");
streamWriter.Write(gtxFile.Heights[nh++]);
}
//next row
streamWriter.WriteLine();
}
}
}
