need help in georeferencing

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03-24-2015 10:47 AM
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New Contributor II

Hi

I have a landuse map which doesn't have any coordinates. However, I have managed coordinates of  around 8 control points in the form of small towns in the map. These points are well spaced from each other. Unfortunately, they are not placed in the corners of the map. Anyway my study area is very small (and most of the control points are close to my study area), as compared to the map, so I hope error percent will be low !! 

which georeferencing method is appropriate to project this map? I am using ArcGIS 9.3.

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MVP Esteemed Contributor

What format is your landuse map?  Is it a polygon feature class/ shapefile?  An image?

You can look here for more details:  ArcGIS Desktop Help 9.3 - Georeferencing toolbar

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New Contributor II

its raster image.

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MVP Esteemed Contributor

You should be able to pick out some landmarks on the image like crossroads etc, and if you have data that supports those landmarks (like a street centerlines feature class of a known projection) you can then create your own control points.

There are several different methods (affine, etc) but I've never done anything but the default and its' always worked for me.  Just follow the help file provided.

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Regular Contributor

I second Joe's suggestion. Add imagery as a basemap to ArcMap, add the landuse map to be georeferenced, and use the Add Control Points tool on the georeferencing toolbar. After all of you control points are added and the landuse map is relatively where you would like it to be run the Rectify tool to output a new georeferenced landuse map with a defined coordinate system.

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New Contributor II

Thankyou everyone. first I projected the image in the desired projection system and then I used landmarks as control points with known coordinates and updated them using georeferencing tool. it worked.