gsinkinson

'Stitching' rasters together

Discussion created by gsinkinson on Nov 8, 2013
I am new to ArcMap and am trying to build a parcel map. I'm trying to figure out a reasonable way to get started.

I have scans of the mylar drawings of the township's tax maps. There are several at 1"=500' and others at 1"=100'. There is a compass rose on each image but each orientation is different.

On several, north points towards the upper right corner of the image, on others, north points towards the upper left corner, and on others, north points to the bottom.

None of the images are georeferenced and any one drawing might contain only one or two points that I could match up in any ortho-imagery. However, if I could 'stitch' the images together, I'd probably have enough ground control points to make that work.

I can identify points where any two images should be coincident (adjacent parcel edges on different maps) but my problem is in trying to rotate and translate each image to align them so that I could then trace all the polygons.

Am I on a reasonable path? If so, is there a tool that would allow me 'stitch' the images together? I tried creating outlines of the groups of parcels on two maps and then tried to 'georeference' them, but with only two nodes that were common across the maps, that doesn't work.

I could use suggestions on how this kind of thing gets done in the 'real world'.

What might be other approaches?

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