Notes for IBW geospatial data
JRA 1_27_03

1) http://aria.arizona.edu/ Arizona Regional Image Archive:
	DEM (not an easy format), DRG and DOQQs

1.5) Copied Maricopa COunty DEM (From ASU GIS lab) mdem; but it has clarke 1866 spheroid and we should use nad27 (use utm zone 12, nad27 for projection and spheroid for this project).

2) ArcGIS: IBWjra1_27_03.mxd project with relative path names
	add above files; build pyramids.  Again problems with spheroids:

DRG:
Coordinate System:
Transverse_Mercator
False_Easting: 500000.000000
False_Northing: 0.000000
Central_Meridian: -111.000000
Scale_Factor: 0.999600
Latitude_Of_Origin: 0.000000
GCS_North_American_1927
Datum: D_North_American_1927
Prime Meridian: 0

MDEM:
Coordinate System:
Transverse_Mercator
False_Easting: 500000.000000
False_Northing: 0.000000
Central_Meridian: -111.000000
Scale_Factor: 0.999600
Latitude_Of_Origin: 0.000000
GCS_Clarke_1866
Datum: D_Clarke_1866
Prime Meridian: 0

DOQQ:
Coordinate System:
Transverse_Mercator
False_Easting: 500000.000000
False_Northing: 0.000000
Central_Meridian: -111.000000
Scale_Factor: 0.999600
Latitude_Of_Origin: 0.000000
GCS_North_American_1983
Datum: D_North_American_1983
Prime Meridian: 0


So all are in UTM zone 12, but we have three different spheroids.
So, what we do is as long as each dataset/layer has a defined projection (if not, do so in ArcCatalogue), we just change the projection of the dataframe that contains those layers and they are all reprojected on the fly.

3) Georeferencing 1962 airphotos:
	ARChelp:  Georeferencing->desribed
	A) 	Rename scanned airphotos with *.tif
	B) 	Open in Photoshop
		Rotate images 90 degrees counterclockwise
		Note 60% overlap
		Crop center 60-80%; saves *.crop.tif
	C) 	Open ArcGIS with drgs and doqqs correctly loaded
		add tif to be georeferenced
		make sure georeferencing toolbar is shown
		select tif in georeferencing window
		click fit to display to get it to appear with the other ones. 
		Position it with the hand tool
		Change its color and transparency by right clicking on it in table of contents.  Display has transparency %, and symbology can let you change the color ramp. Also note that you can alternate the upprmost layer by dragging them above eachother in the table of contents.
		Add control points.  Go from the tif to the map or other image.
		After 4, look in the links table to review error (RMS).
		Make sure to save the links file.
		When satisfied, rectify (under menu on georeferencing toolbar and save with new name that let's us know that it has been rectified).