====== Autodesk Land Desktop: Establishing a Spatially Accurate Drawing ====== This procedure will create a drawing project that will be accurate with planar coordinates as well as spatial coordinates, such as Latitude/Longitude. ===== Prerequisites ===== * a known point in the drawing, representing a Latitude/Longitude * rotation of true North, if not straight up * a local geodetic coordinate system, using the same units as your drawing ===== Scope ===== * define a spatial coordinate system for the drawing coordinate system * allow a local coordinate system to be used, such as for surveying purposes * allow .shp files to be imported accurately ===== Procedure ===== (this will be shown after the project has been created, so that older files may be updated as well) - open an existing project - go to Map -> Tools -> Assign Global Coordinate System - select the appropriate coordinate system for the file, using the same units (Example: Category=USA,Arizona, Coordinate System=HARN(HPGN)Arizona State Planes, Central Zone, US Foot) - if you have objects in the drawing, you may need to move them now to match up with the coordinate system you just selected * tip: if you don't know the coordinates of the local system, but you do know the WGS84 Lat/Long, simply use the Map -> Tools -> Track Coordinates tool to digitize a point using WGS84 Lat/Long (or any other system); then move your objects to the new point - once your objects are positioned properly in the drawing, you may want to set up a custom Northing/Easting (such as for surveying) - Projects -> Drawing Setup -> Orientation tab - use the Base Point dialog to select a point on your drawing that will correspond to a Northing/Easting (entered on this same page) - you may also use the North Rotation to define another direction for North, rather than straight up - you should now be able to: * import/export survey points with a custom coordinate system * import/export ESRI .shp files accurately * digitize, locate, inquiry etc... any point on your drawing, with geodetic accuracy ===== Points of Confusion ===== * the Autocad coordinate system (X,Y) will have to match up with the local coordinate system of the earth, such as HARN(HPGN)Arizona State Planes, Central Zone, US Foot * your points will NOT use the Autocad coordinate system (X,Y), but instead use a Northing/Easting as defined in your drawing setup orientation