[Gllug] Cartography software

Walter Stanish walter.stanish at saffrondigital.com
Tue Dec 29 09:20:53 UTC 2009

> I have a series of maps covering aproximately the same area. They are at 
> different scales and the scanned images are different sizes and orientations.
> Do any of you know of any packages which would (ideally) be able to resize and 
> otherwise adjust the images so they can be overlaid on each other?

GIMP or possibly inkscape (don’t know offhand if it lets you drop in bitmaps)
Will let you do this interactively.

However, it really depends what you want to overlay them for.

For example, if you are building a geospatial dataset from scanned sources 
(heheh... been there, done that!) then you may be better off using Google Maps
API and a custom overlay to enable you to automatically achieve latitude/
longitude for points you select.

That way you also get the benefit of at least one extra source, being google
Maps satellite view ... and possible two, ie: Google Maps.

Guessing another use-case, if you are looking to resize a new map (or two) to
meet an existing map's registration (eg: if you have manually stored points on
this map using X/Y offsets), then you can often (depending upon accuracy and
projection type) use an algorithm to determine required scaling based on the
registration of three common points across all maps.

Hope that helps.

- Walter

(I used to a decent sized custom geospatial database with X/Y offsets and a
 Javascript-based interface in the pre-Google Maps days, so have felt your 
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