shrug-l: ArcGIS: Spatial Adjustment

[Bill Porter]

I've had good luck scaling CAD drawings to aerial photos or City/County GIS
roadwork and to survey-grade GPS points.

FAMU physical plant has no mapping resources. They depend on CAD sketches
that are not tied to real-world coordinates or distance unit. Some are
precise in relative dimensions, some are truly terrible. Some are in inches,
some feet, some nothing.

If the CAD has features that correspond to any features in my known GIS data
I take careful measurements:  measure the width of a road [or any feature
common to both] at one point in the X direction in the CAD and GIS files,
then another in the Y direction.  With those measurements I set up a simple
proportion in the CAD file and the GIS files, set up a simple and scale the
CAD drawing accordingly. It's easier if X and Y proportions are the same,
but AutoCAD is tolerant.

Once the size is correct in the CAD drawing it's easy to move the drawing to
the correct location over a known layer.

This system assumes you have precise GPS [RTK or post process] OR AutoCAD:
If you use CAD it works best when the CAD drawing represents a feature like
a parking lot or new building in an area within a GIS coverage.