## SpatialReference

**Summary**

Projects all points in a grid or shapefile from the
original

coordinate system to a new coordinate system using Proj.4
(proj.dll).

**Functions**

ProjectGrid |
Transforms a grid from one coordinate system to
another. |

FillGrid |
Fills the result grid with values from the input
grid. |

ProjectGrid |
Transforms a grid from one coordinate system to another. For large grids (>50MB) use the save-to-file version of this function. |

GetUTMZone |
Returns an appropriate UTM zone given a longitude in
degrees. |

ProjectShapefile |
This function has 3 overloads. |

Distance |
Computes the distance between two values. Minimizes the chance of overflow by not taking the square of any number. |

ConvertAndProjectPoint |
Projects a 2D point from one coordinate system to another using Proj.4 function: pj_transform. This function assumes that the caller has already checked to see if conversion to radians or degrees is necessary, then performs the necessary conversion before or after projecting the point. |

ProjectPoint |
Projects a 2D point from one coordinate system to another using Proj.4 function: pj_transform. |

FreeProjPointers |
Releases memory used by the srcPrj and destPrj
structures. |

GetErrorMsg |
Returns the error message associated with
prj_transform. |

InitializeGlobalVariables |
Sets the global projection variables: srcPrj, destPrj,
convertToRadians, and convertToDegrees. |