Georeferencing jpg map without any digitizing data using Google Maps

Question

I have only a jpg map but don't have any digital data for georeferencing that jpg.

Is there any way for georeferencing my map (like Google Maps)?

Answer 1

Yes there is, but before that, what software do you have available? To georeference a non georeferenced jpeg you will need to know/have one of two sources of information.

1) Access to vector or raster data that covers the same geographical area in the jpeg 2) Knowledge of the geographical extents of the jpeg (ie: Lat/Long cooridinates or UTM coordinates)

With this information you can georeference the jpeg in a GIS software package such as QGIS, ArcGIS, ERDAS Image, PCI Geomatica etc.

Here are three links to how you would perform this task.

http://courses.umass.edu/nrc297s/PDFs/Lab_Georeferencing_with_QGIS.pdf http://ocw.tufts.edu/data/54/626689.pdf http://adielflitzow9.files.wordpress.com/2008/02/georectify.pdf

Answer 2

To georeference an image, you should know the lat/long values of at least 3 locations on the image. The more the better. These are called GCPs (Ground Control Points). Once you have the GCPs, you can transform the image to fit in a real world coordinate system (like lat/long). Many times you can get coordinates from the markings on the scanned map image itself.

This help article has useful information for ArcGIS 9.3 http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=Georeferencing_a_raster_dataset

If you want to try this in QGIS, I have a step-by-step writeup http://qgis.spatialthoughts.com/2012/02/tutorial-georeferencing-topo-sheets.html