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Converting a scanned map into GIS data. John McVay. My Field of Study: Environmental Science with a concentration in Community Land Planning. Career Aspiration: work for a land trust. How can this skill be applied?.
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Converting a scanned map into GIS data John McVay
My Field of Study: Environmental Science with a concentration in Community Land Planning. • Career Aspiration: work for a land trust
How can this skill be applied? • Project that this information comes from prioritized areas for habitat protection – what some land trusts do. • Sometimes work in remote areas with no previously prepared GIS. Physical map may be all you start with. • As a planner, you can create new features in GIS by sketching features on the scanned map
But First… You Have to Get Scanned Map Set Up in ArcGIS How to do this: • Open scanned image in ArcMap, click yes to build pyramids.
Set coordinate system • Determine x,y coordinates for control points - Zoom in enough so that you can read the coordinates - Coordinates along the top and y-coordinates down the left side
Adding Coordinates: • Zoom in • Display the Georeferencing toolbar. • Click the View Link Table button • Click the Add Control Points button • Position the crosshair so that it lines up precisely with the intersection of the blue tic mark and the black line of the map border.
Right-click and choose “input X and Y.” • Enter x and y coordinates • Once all four coordinates added, to permanently apply the transformation to the data, you must use the “Rectify” command from the Georeferencing menu