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Digitizing and Geocoding Old Maps? 235

Posted by timothy
from the walking-directions-rivendell-to-el-dorado dept.
alobar72 writes "I have quite a few old maps (several hundreds; 100+ years old, some are already damaged – so time is not on my side). What I want to do is to digitize them and to apply geo-coordinates to them so I can use them as overlays for openstreetmap data or such. Obviously I cannot put those maps onto my €80 scanner and go. Some of them are really large (1.5m x 1.5m roughly, I believe) and they need to be treated with great care because the paper is partly damaged. So firstly I need a method or service provider that can do the digitizing without damaging them. Secondly I need a hint what the best method is to apply geo coordinates to those maps then. The maps are old and landscape and places have changed, it maybe difficult to identify exact spots. So: are there any experiences or tips I could use?"
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Digitizing and Geocoding Old Maps?

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  • Handheld scanner (Score:4, Insightful)

    by rbcd (1518507) on Wednesday March 10, 2010 @05:43PM (#31431416)
    Why not use a handheld scanner and some stitching software?
    • Talk to a curator (Score:5, Informative)

      by The_Wilschon (782534) on Wednesday March 10, 2010 @06:02PM (#31431690) Homepage

      Another possibility would be a really high resolution digital camera. My wife (historical linguist) has dealt some with manuscripts, and that was their method of digitizing them for further study. OTOH, she's not a museum curator or archivist; they probably have even better methods. If you want to do it right, talk to a curator or archivist of some sort. They deal with much more fragile and much more valuable documents on a regular basis.

      I don't have any good ideas to contribute about the geocoding, unfortunately.

      • Yep. Glass over map, good high-resolution camera mounted above (as far as possible), long steady exposure. Maybe some stitching afterwards.

      • by KlaymenDK (713149) on Wednesday March 10, 2010 @07:03PM (#31432366) Journal

        Seconded. Get some quality gear. As in, contact your local university or museum, they are bound to have (connections to some place with) the proper equipment.

        What's this for? If you would be willing to donate digital copies, or even the originals (if you feel they would be better able to take proper care of them), I bet they would gladly provide the time and resources.

        Good luck!

      • Re: (Score:3, Informative)

        by artson (728234)
        For alobar72; this is the sort of problem I sometimes had when I was in the Canadian Foreign Military Mapping Agency a few years ago. A few things come to mind: such as your location. Where you are will affect your options.

        I'll assume you are a European and suggest the nearest large university cartographic library. They are knowledgeable, helpful and it's the sort of thing they do. They are also all in touch with the other universities, so you will have lots of resources to draw upon.

        If you are in an ex-c

      • Re: (Score:3, Interesting)

        by Anachragnome (1008495)

        The geocoding is going to be a BITCH.

        The scanning, you'll find out is going to be the easy part.

        As a collector of maps, you should know that old maps use different projections to display a 3D object on a 2D surface--the Earth on paper--and that in addition they also use different scales. Sometimes convention is tossed out the window and a map uses neither standard projections nor consistent scale. The older the map, the more this is likely.

        In order to apply coordinates to these maps, coordinates that are us

        • ...that can be stretched to align properly.... Any graphics whizzes out there that can expand on this?

          There's a free program -- autostitch.exe -- that does a superb job of combining images into a panorama. It's a "demo" but is very suitable for your map-scanning application.

          To generate a panorama image, the camera (lens, actually) is kept at one position and panned left/right/up/down to create multiple overlapping images that fully cover the scene. I've combined up to 154 JPGs into a single panorama. I

          • Re: (Score:3, Informative)

            by ZosX (517789)

            you could also try hugin and play with the various projections that are rectangular. hugin uses autopano-c and seems to work pretty good. ideally get yourself a copy of photoshop cs4 and just use file->automate->photomerge and try automatic and then "reposition only" if it is for some reason trying to project on a spherical surface. the lack of seams and stitching errors in photoshop's tool really amazes me compared to other pano programs I've used. I really liked hugin and did a lot of cool stuff wit

        • Re: (Score:3, Insightful)

          by Jaysyn (203771)

          It's called rubbersheeting & and some GIS suites can help you do it, or have extensions that will. Pretty sure AutoCAD Map can do it too if you have Raster Design installed.

          http://en.wikipedia.org/wiki/Rubbersheeting [wikipedia.org]

        • Re: (Score:3, Informative)

          by Jon_S (15368)

          Raster reprojection is done all the time in GIS, so this would be nothing new. Google Earth has plenty of georferenced old maps available as overlays, and I've made a few myself. Yes, some distortion would be introduced by the camera (as opposed to scanning), but since the projections may be arbitrary or off anyway, all this gets corrected at the same time.

          It is true that you have to have some common points to current georeferenced maps in order to do this, of course. But there should be enough, and if n

      • We deal with old data with weird and sometimes unidentified projections fairly often. You will need at least some landmarks, though. The larger the scale, the more you will need. The more complex the projection, the more landmarks you'll need. With really old maps that are hand drawn and don't match a distance scale (pre-17th century) you're probably out of luck even if it's a local street map.

        Astronomical software to deal with converting between projections is typically open source, but the learnin

    • Re: (Score:3, Informative)

      by Rei (128717)

      I was going to suggest the same thing -- two birds with one stone. I personally use Hugin for things like that. You take many high-res, overlapping photos. You can automatically match them up with autopano-sift and then use vertical and horizontal alignment points to stretch them out as you would prefer. If the results aren't close enough to use as an overlay as-is, if you had a hires modern map, you could load it and set the FOV to roughly match up with the FOV of your fully aligned pieced-together map

    • Re: (Score:3, Informative)

      by mpapet (761907)

      Yowza, that would be a royal pain to get results.

      Two ways to go.

      1. Wide format scanner. These are usually at more specialized digitization shops. Find someone who scans blueprints in your area. http://www.amazon.com/Designjet-Large-format-Scanning-Software-Intergrate/dp/B000E8Z0XU [amazon.com]
      Only you can judge if the documents will be okay through the feeder. The feeders aren't hard on documents. I'd give your best one a shot. Naturally, you want to be there. So, not every service provider will be okay with that.

      • Re:Handheld scanner (Score:5, Informative)

        by toastar (573882) on Wednesday March 10, 2010 @06:21PM (#31431930)

        I do this for a living, We Use a wide format scanner and Global Mapper to georectify them.

        Contact mikes@wavefront.pro if you would like a quote.

        We do everything from old torn maps to vellums to Tifs, We can Georectify them to load quickly as a geotiff. or we can digitize the data on the maps into Arc compatible Shapefiles.

        • Re:Handheld scanner (Score:5, Informative)

          by toastar (573882) on Wednesday March 10, 2010 @06:23PM (#31431952)

          We can also output Google Earth KML's. It's neat to be able to click a link and get all your contours and well locations to pull up in 3D. And to have this file work on any machine with google earth.

      • by Gilmoure (18428) on Wednesday March 10, 2010 @06:41PM (#31432140) Journal

        Or contact local university geography department. Might be able to work up some program with them to have students do the digitizing.

        • by hardburn (141468)

          This, please. Mod this to the sky. These maps no doubt have historical value and if they need to be handled carefully, then give it to people who are trained to do it.

          • by Gilmoure (18428)

            I was thinking more of the digitizing/correcting of the scans/images. Maybe a university might have a place that can handle archival type stuff but don't know anything about that. /geography major for one year. Did a lot of digitizing for projects the school was working on; police maps, utility maps, etc. Lot of grunt work.

      • Good advice so far, scan it and stitch it. Once you have that, just release it under a creative commons license, and ask for help with your goal. The crowd should be able to help you with the rest. Some will do an overlay with a fish-eye. Some will do an overlay with a small rectangular mask. Some will try morphing the different maps using the edges and/or the landmarks that can be recognized as reference points. It may not come out the exact way you originally envisioned, but with a bit of playing around w

    • by icebike (68054)

      Hand held? That would be a mess.

      To the OP:

      Almost every bigger city has an artist community and almost any art shop will be able to point you to people who specialize in super high resolution scanning. (For a price, but its not usually unreasonable.)

      The file sizes will be huge.

    • by TheMCP (121589)

      For that matter, why not use a digital camera and some stitching software?

      Or, if you've got a good way to align a map against the lat/lon grid (which you'll have to have or you won't be able to use the maps anyway), why bother stitching it at all? Just photograph the map in sections, and use your alignment method to align each section separately.

  • dig camera (Score:2, Informative)

    by YrWrstNtmr (564987)
    Proper lighting, focus, tripod, and a large enough flat surface should produce pretty close to scanner results.
    Faster than the scanner and stitching.
    • by Hadlock (143607)

      A lot of people now recommend SLRs for old/ancient family photos that have been framed. In most cases an SLR is going to give you the quality you need. For internet caching purposes, 72dpi is plenty good enough.

      • Re: (Score:2, Informative)

        by vcgodinich (1172985)
        You never print anything that you care about at less than 400 dpi (as a rule of thumb)

        If you are archiving things with a 15 mp slr you are missing ALOT of detail that the prints have. I agree that prints stuck to glass are a challenge, but taking a picture with a current slr is a last ditch option.

        • by toastar (573882)

          250-300 is fine for scanning, you can always drop pixels, It's a lot harder to bring them back. Always keep the Hi-res's.

        • by Joce640k (829181)

          It could work ... you'd take lots of closeups and stitch the results together.

    • Re:dig camera (Score:5, Informative)

      by vcgodinich (1172985) on Wednesday March 10, 2010 @06:02PM (#31431686)
      no no no.

      Been there, fought lighting and camera distortion for hours, only to get bad quality (relative to a scanner)

      Lay the maps out on a uniform surface, take the lid off a nice scanner and turn it upside down and move it place to place. Use rather big (1-2inch) overlaps, because the edges of the scanner sometimes are incorrect. You can make a batch process to crop the edges off in photoshop / gimp.

      Most important is to lock down scanner settings so nothing is auto, or you will have colorcontrastluminosity differences between sections of your map.

      Stitching these together requires 0 effort in any modern photographic editing software.

      This is cheap, gives the best results and is the only way to get good quality without spending a fortune or damaging the documents.

    • by toastar (573882)

      Proper lighting, focus, tripod, and a large enough flat surface should produce pretty close to scanner results.
      Faster than the scanner and stitching.

      It's note just a flat surface, the glass also sort of forces the paper flat. You would need a large heavy piece of plexiglass for this setup as well for the crinkly maps.

  • Contact a Museum (Score:5, Insightful)

    by Speare (84249) on Wednesday March 10, 2010 @05:47PM (#31431470) Homepage Journal

    I suggest you contact the restoration experts in major museums for (1) advice about preservation, and (2) how they go about their own digitizing projects. I read a fascinating article about the digitization of many medieval parchments, but I don't recall the particular museum involved now.

    • Re: (Score:3, Informative)

      by ILikeRed (141848)

      I agree, you might try contacting someplace like David Rumsey Historical Map Collection [davidrumsey.com] to see if they would be interested in helping, or might otherwise make recommendations.

      A collection of other links that might be of interest:
      Historical Map Web Sites [utexas.edu]

    • by MMC Monster (602931) on Wednesday March 10, 2010 @06:10PM (#31431796)

      How about asking the real experts: Google.

      I don't mean googling for an answer. I mean actually emailing someone at google to see if the people they have involved with book scanning may have some ideas. At the very least, if you peaked someone's interest there, they may point you towards the right people in the restoration business.

    • Re: (Score:2, Informative)

      by ngrier (142494)

      If the maps are in decent shape, you typically use a large-format scanner. These are extremely expensive, though, so you'll preferably want to find a local university or friend at a company with one. Most larger copy shops will have one (for making architectural plans/construction documents) but will likely charge you a pretty penny to use it. And as others have pointed out, uni or a local historical society may have been through this so be relatively set up to guide you along (or even do some of it for you

  • by fahrbot-bot (874524) on Wednesday March 10, 2010 @05:48PM (#31431486)

    Obviously I cannot put those maps onto my 80 scanner and go. Some of them are really large (1.5m x 1.5m roughly, I believe) ...

    I have a map of the U.S. - its actual size. The legend says "1 mile = 1 mile".
    People ask me where I live and I say, "E4".

  • Is this in the US? (Score:3, Informative)

    by Sycraft-fu (314770) on Wednesday March 10, 2010 @05:49PM (#31431506)

    If so, give USGS a call. They may well be interested in helping you with this and obtaining data from the maps. I can't say for sure, of course, but this is the sort of thing they do. When it comes to map data for the US, they are the go to guys. Call them up, tell them what you've got and what you want to do, see if they can put you in touch with someone in their agency who'd be interested in helping.

  • by eldavojohn (898314) * <[moc.liamg] [ta] [nhojovadle]> on Wednesday March 10, 2010 @05:51PM (#31431526) Journal
    I'd suggest appealing to Google or the brothers that did tapestries for the Met [slashdot.org]. What are these maps of? Is there a society for the place that they cover where you could appeal for funds under the pretense that you publicly release the maps?

    Assuming all those avenues are exhausted, let's look at some cheap and dirty DIY methods. I'm assuming you've got a MP digital camera. There are sub $100 ten megapixel cameras [amazon.com] out there but don't get anything with a fancy digital zoom. Next you'll need mosaicking software [aolej.com] or if you're into software, you can try your own implementation of the KLT algorithm [clemson.edu].

    First off, practice all of this on layed out newspapers while developing your preferred methodology.

    Your cheapest and most haphazard option is going to be lay the maps flat on the floor and cut a length of string with a washer on it (two to three feet?). Try to use brightly diffused lighting so that is normalized in the mosaics with no shots of your shadow over the maps. Now this is backbreaking but hold the camera flat over the map with the string extended in front of it so you can keep the distance to the map consistent. Don't angle the camer as this will slightly distort that tile and hinder the mosaicking. Put plastic bags on your feet if you need to walk on the maps. Take a picture, move a few feet in a grid style, take another picture. Rinse, wash, repeat until you have images covering all of the map. Collect the images and put them on the computer and verify the mosiacking works before preparing the map for storage forever.

    A better method would be similar but to construct a large wooden rectangular box with plexiglass as a top so that you can fit this structure over the largest of the maps. Then cut holes in the plexiglass so that you can set your camera at a plane level to the surface of the map into the plexiglass. You might want to put an adapter on your camer that allows the lens and flash to be free of obstruction. You could make the tiles more uniform and save your back some work but you need to build and buy the materials for the structure. I think this is more time consuming but your best bet and will allow you to gather more images with less distortion.

    Above all, remember to save the original images! It's probable that later better algorithms will be developed to normalize the images, remove distortions, light problems, shadows and increase clarity on your overlapping sections. If you do the plexiglass route, you could manufacture it so that every bit of the map is photographed three or four times.

    Not professional, not flawless but cheap and dirty. Hope this helps.

    As for the geocoding, what are the maps of? You should actually check out the feature extraction of the KLT algorithm and consider using that methodology for syncing these up with maps. That will require human intervention though to identify the features, I'm sure.
  • Hard to Do (Score:5, Informative)

    by carp3_noct3m (1185697) <slashdotNO@SPAMwarriors-shade.net> on Wednesday March 10, 2010 @05:52PM (#31431540)
    I actually have a strange fascination with old maps myself, and regularly crawl the web for all kinds of antique maps. One overwhelming commonality I have noticed is that even recent maps can often be wildly wrong. So for example, an 1600ish map of Europe will be so wildly inaccurate that you would only be able to pick one point on that map to apply geolocation specific coordinates, the rest would not match up. So, I know I didn't answer your question, but I just think that unless they are accurate maps, it would be a very hard challenge.
    • Re: (Score:3, Insightful)

      by tbradshaw (569563)

      Well, that's certainly true if you apply a specific scale to the map, but another method would be to attach geo-coordinates to landmarks on the map and then use interpolation to determine location otherwise.

      In this way, if you were "moving on the map" between two locations that are a different distance apart on the map than reality, your "dot" would just move faster. Positional accuracy would be a continuum that increases in accuracy the nearer one is to a particular point of interest.

      • I was thinking the same thing. I think this is a great idea for a SIGGRAPH type of project, and one that might even have some useful implications for historians.

    • It might be interesting to see how many control points you would need to distort the maps (along a spline or something) and get quite close to accurate.
    • by martas (1439879)
      one possible solution would be to find a set of potential reference points, and then apply some kind of transformation on the map so all the points match their true positions at once. would be a fun thing to look at. though you'd need some assumptions about the nature of error in maps, i.e. what sort of distortions did people draw with in the first place. and you'd either need experienced mapologists for that (yeah i know that's not a word), or tons of data.
  • by molo (94384) on Wednesday March 10, 2010 @05:53PM (#31431566) Journal

    You might want to find the local university cartography or geography department. They will probably already have a method of doing this, or at least could point you to someone who does. Here's an example: http://mapmaker.rutgers.edu/ [rutgers.edu] and their historical maps: http://mapmaker.rutgers.edu/MAPS.html [rutgers.edu]

    -molo

    • by Lunatrik (1136121)
      I second this - if you happen to live near Atlanta, GA Georgia State has a nice cartography / GIS lab. UGA used to as well. Most state colleges will have a geography program or GIS certificate, either way you go you should find people ready and willing to help!
  • OP didn't mention if these maps have lat/long data in them. If so then you are good to go with using Google Earth and it's KML format to describe the map and it's inherit location on the globe using lat/long points of known locations or map end points.

    If you do not have lat/long you may need to match up the map with an existing map using something like google earth and overlay it until it lines up properly. Then you can get the end points for the map and, again, use KML to describe where it should reside.

    • by codegen (103601)

      Lat/Long mapping is what he is probably after. The latitude of a particular location is not exactly fixed. It depends on the reference geode used. You can have three maps of the same location specify different latitudes. GPS, for example use WGS84, but many older maps in North America use NAD 27. Official Gov of Canada maps use CSRS. In fact better GPS units allow you to change the reference geode in the software to match the one on your map.

      If you take a map with coordinates in WGS84 and try to align it wi

  • by RingDev (879105) on Wednesday March 10, 2010 @05:58PM (#31431634) Homepage Journal

    Really, history majors will love this stuff. Giving them maps and a concept of Google maps overlays for real time comparisons to modern maps will likely be a capstone project for some undergrad.

    A few years ago while working for the State of Wisconsin's Board of Commissioners of Public Lands we worked with the University of Wisconsin: Madison to get all of the original land plat maps of the state digitized, indexed and search-able. Same type of deal, huge maps on really old paper that had to be vault kept with humidity and temperature controls.

    -Rick

  • Digicam? (Score:3, Interesting)

    by natehoy (1608657) on Wednesday March 10, 2010 @06:01PM (#31431666) Journal

    Focus on the preservation of the imagery first, obviously, because once that's gone it's gone forever.

    The cheapest option is a large-megapixel digicam known for good image quality. SLR would probably be a good bet. You can take multiple images and stitch them together without too much trouble, so you can get reasonably fine detail with a little work even with a $200 consumer camera. Or, alternatively, hire a professional photographer and have him/her take really high resolution photos of the maps. The advantage of this approach is that you don't have to take the maps anywhere or do anything special with them. Just lay them out on a low table or the floor and align a camera over them, and take heavily-overlapping shots.

    Large-format scanners might cost some serious coin even to use for a one-time project like this, but would probably yield better results with less effort.

    You might check with local companies that deal in maps and cartography, they might be able to recommend ways of saving the imagery, and some might even offer to help out if the maps may be of commercial interest (they might even share the proceeds with you in addition to giving you high-res digital images).

    But I'd say if the maps are truly delicate, your first focus should be to take the highest-resolution images you can of them now, even if it's multiple images per map that need to be stitched. That way, you have *something* preserved in case one or more of the maps is destroyed or deteriorates further before you can preserve it.

    If there are particularly interesting features of the map, use the MACRO feature on your camera - most stitching programs can integrate images at different scales and preserve a lot of detail. I used the "Hugin" pano toolkit (free) to stitch together about 100 random photos I took at the top of the Eiffel Tower into an impressive contiguous 360 panoramic shot, and it was literally a "here are the pictures, figure it out" process. The pictures were all taken at different zoom levels, different angles, and all sorts of issues, yet it looked like a Google Street View 360 image. This was 5 years ago, I can't imagine how much better the technology is today.

    The geolocation shouldn't be all that hard - it's a matter of choosing a few points on the map and identifying their coordinates accurately. Of course, if there are few/no reference points it gets a lot harder. http://www.openstreetmap.org/ [openstreetmap.org] is a good starting point to a group that does free, open-source mapping. They or some of their related sites might possibly have a tool that does what you want. Also, a professional cartographer may be able to help you out as well.

  • This'll sound stupid, but call your local municipal government. My city, for example, has a nice big scanner that works well for old and well-worn maps. They might even scan the maps for free, esp. if they can keep copies (if your maps include their jurisdiction). Your other option may be to contact a blue-print or architectural printer - even if they don't offer this sort of service, they may know someone in your area who can help.
  • We can help! (Score:5, Informative)

    by Richard Fairhurst (900015) on Wednesday March 10, 2010 @06:03PM (#31431700) Homepage

    First, ask on the OpenStreetMap mailing lists. There's lots of us who've done this kind of stuff before, and we'd be really pleased to help. I collected, scanned and rectified the Ordnance Survey's New Popular Edition - a complete set of England and Wales maps from the '50s, now out of copyright. It's all available in OpenStreetMap as a background layer and loads of people use it for adding rural roads, rivers, placenamese etc. Others are scanning other old Ordnance Survey series right now. Seriously, we love this kind of stuff. (#osm on OFTC can help too.)

    Secondly, GDAL [gdal.org] is definitely your friend. It's the most amazing set of command-line tools for rectifying and reprojecting data. gdalwarp and gdal_translate are probably the two you'll use most.

  • I'd take a look at some of the projects at Metacarta labs (http://labs.metacarta.com/). I worked there for a couple years, and they do a lot with converting old maps into digital, interactive versions. If you get in touch with them, they have some super-enthusiastic people who can give you great advice.

  • ... that can handle just about anything. I had a very large historical map/timeline (maybe 1m x 2m) scanned by a professional service, and they did a very good job. This was years ago. I would think you could find someone in your part of the world to do it.

    I also posted here to say that I think your project is a very worthy one. Good luck!

  • Google Them (Score:3, Funny)

    by imscarr (246204) on Wednesday March 10, 2010 @06:07PM (#31431770) Homepage

    Take photographs of them and put them on the internet. Google will automagically index them and add them to their street maps in real time.

  • Google for GeoTIFF and spend some time here [slashgeo.org]

  • Buy or borrow a high-end DSLR. Lay your maps out and provide good lighting (avoid using the flash). Because the images you produce will contain a lot of hard lines, any decent panorama software will stitch them together beautifully. I recommend Hugin, which is free. PhotoShop CS2 or better, if you have it, also does a really good job.

    Feel free to send me a copy. I love old maps.

  • by spandex_panda (1168381) on Wednesday March 10, 2010 @06:12PM (#31431820)

    Hi there, I am a spatial guy so thought my 0.02 may be worth something. I am not too sure about digitising them, maybe a print shop or as suggested in other posts you could talk to your local university geography department or a government mapping agency

    Once they are digital though you need to georeference them. As mentioned in the title of my post, it is easiest to use GIS to do this and you can use QGIS with relative ease. Install it using osgeo4w [osgeo.org] on windows or the ubuntu ppa for qgis [launchpad.net]. Alternatively if you have a license then use ArcGIS. If you have a map of the underlying roads for the maps you are digitising then what you do is find points on the roads and match them to points on the scanned images, this provides data for a transformation and will shift the map onto your coordinates.

  • Find a service provider or museum with a digital Cruzcam. They are a copy stand with an integrated camera/scanner system meant for exactly what you need.

    Madcow

  • by TimmyDee (713324) on Wednesday March 10, 2010 @06:15PM (#31431846) Homepage Journal

    I spent a summer doing this in grad school for the Vegetation Type Mapper [berkeley.edu] project at UC Berkeley. I'm not going to lie to you--it was a ton of work. But the results were cool. The site has all the old maps georeferenced, plus ways to download them.

    Needless to say, the library was involved in the project, as was a giant scanner. We relied on ERDAS Imagine software to georeference the old maps to current USGS base maps. There was also a lot of accuracy assessment involved to make sure we minimized error in the georeferencing process. Probably one of the trickiest parts was making sure the old landmark you were using as a control point had not substantially changed in the intervening decades.

    My professor and her colleagues published a paper detailing the project [berkeley.edu].

  • Geocoding (Score:5, Informative)

    by spasm (79260) on Wednesday March 10, 2010 @06:16PM (#31431866) Homepage

    Others seem to be describing some good solutions to getting the map scanned, so here's how to geocode and rectify the image using the open source Grass GIS software:

    Step 0:

    - You need to have a location already created in grass, with some contemporary data in it (physical features, roads etc where there's some concurrence with the map you're trying to geocode). The projection you've used doesn't matter much - a later step is going to be rectifying (ie distorting) the scanned map to match the projection of the digital map. The created location does need be at least as large as the scanned map (ie if the map is everything in a 5 km radius of some town, the grass location also needs to encompass at least a 5 km radius of the same town).

    Step 1:

    - Come up with a list of features/points which exist on both maps. Depending on the scale of the map, this could be intersections of specific roads, locations of towns, peaks of mountains etc. You're going to need an absolute minimum of five points for the rectification process to have any chance of working; more than fifteen is much better. Try and select points which are unlikely to have moved over time (coastline or river features for example). In grass, mouse over each point and record the coordinates.

    Step 2: import the scan

    In grass, do: r.in.gdal input=[path to scanned file] out=[Mapname] location=templocation

    Quit grass

    Step 3: target, point, rectify

    Open grass, but this time in the 'templocation' you created in step 2

    i.target group=groupMapname location=[modern map location name] mapset=PERMANENT
    i.group group=groupMapname in=Mapname
    d.mon start=x0
    i.points groupMapname

    d.mon will open a window; i.points will display the scan in it. Select the mapname in the dialog that appears, then one by one select each of the points you've identified as having concurrence with the modern map. In the terminal window, enter the coordinates for the point taken from the list you created in step 1. When done marking points, click 'quit'.

    i.rectify -a group=groupMapname extension=_1 order=1

    Depending on the size of your map and your processor speed, this bit may take a while. When done, quit grass.

    Step 4: admire output

    Open grass in the modern location. The scanned map will be available as a raster layer for display. The scan will have been rectified so the map matches the projection of the modern map layers - ie you'll be able to see what's moved and changed, and what exists now that didn't then etc. There's other grass commands which will help you convert features of interest (rivers, roads, contour lines, whatever) into vectors if you really want.

    If all this seems too hard, have a look at qgis - also open source mapping software; it's more gui-oriented and I know it has a georectifying plugin. I've just never used it.

    Good luck.

    • Geomorphic stability (Score:3, Informative)

      by SpaceMika (867804)

      Just a pedantic little thing -- as a geomorphology instructor, I can tell you that rivers and coastlines are very, very likely to have changed. Check out pretty much any river mouth in Victoria, Australia, or any island off Maine, US in google earth vs google maps satellite mode for examples of how much they can change inside of just a few years. If something catastrophic has happened (big storm, big earthquake...), huge changes can shift the coastline inside of hours.

      If you're going to use geomorphic featu

      • Re: (Score:3, Insightful)

        by demonlapin (527802)
        Although it's not totally clear from his phrasing, I believe that he meant to avoid rivers and coastlines, but he phrased it badly.
  • Saw a great presentation at OSCON a few years back about the massive digitzation effort undertaken by David Rumsey (http://en.wikipedia.org/wiki/David_Rumsey): See http://conferences.oreillynet.com/cs/where2005/view/e_spkr/1867 [oreillynet.com] -- Drew a well-deserved standing ovation.

    In the course of the talk, I think he said that he'd scanned the first 10,000 maps (though even 1,000 sounds ridiculous -- maybe it was 1,000) before hiring assistance.

    Of course, he had more money to play with, so he probably had a pretty big

  • Several people have mentioned good resources (museums, local government, geography dept., etc.). I'd add university libraries to that list (especially the maps or special collections departments). But the most important thing is location. Since you don't want to move the maps more than necessary, and if the maps are of your local area, then the library/museum/government in your area will be most interested in them.

    For geocoding the maps, I think you'll need to figure out what you're going to do with them

  • by anlprb (130123) on Wednesday March 10, 2010 @06:25PM (#31431976)

    Contact a local Licensed Land Surveyor. We are in the business of coordinating maps and making sure they are properly referenced. We also know the difference between NAD83 and NGVD29. This and the other coordinate system conversions and the proper use of scale factor in SPCS (State Plane Coordinate Systems) is something we do every day. Plus, most of us are really into local history and could possibly show you some other really neat uses for that data. Historic societies are always looking for ways to map past events. When speaking with a Surveyor, we can usually know what the practice for a given time period was. There are three different lengths for a foot that I have come across working. International Foot (not used in surveying, but sometimes engineers use the wrong foot), US Survey Foot (standard) and the Philly Foot. Philadelphia has a different set of standards for how a long a foot is, depending on what part of the city you are in and what you are trying to do. This is not something most historians would accurately pick up. Surveyors will. We also know who was the good and not so studious Surveyors in the area and what tricks each used to mark corners, turning points and reference markers. A local Surveyor in the area the map is of would be very interested in helping you with your work. He/she may have already done the heavy lifting for you. We have to trace maps back as far as possible, so sometimes (I am in New Jersey) we have to go all the way back to the Proprietors to get maps so that we can run lines that control our current work.

    Long story short, if it deals with cartography or local surveying, seek a professional Surveyor.

    • by garyisabusyguy (732330) on Wednesday March 10, 2010 @07:16PM (#31432460)

      If you are having a hard time finding a surveyor, just go to the closest construction sight and find a guy that looks like the sun has baked him into beef jerky and that has orange and pink ribbon hanging out of his truck.

      If you are not really certain, just ask him where the closest pcc is and he will give you an hour long spiel about the advantages of pccs over spirals.

      At this point you should realize that you would rather talk to a GIS professional than a Surveyor, if only to save your sanity. Trust me, I have been both and LS's can be a drag.

  • I've done this (Score:5, Informative)

    by sidb (530400) on Wednesday March 10, 2010 @06:42PM (#31432162) Homepage

    I have done this for a grant-funded historical map digitization project at a university library. We used a $40k large-format scanner (from Betterlight) which can scan the whole item laid out flat. Trying to stitch together camera images will result in distortion across the image—if you didn't need to distort it, you wouldn't need special software to do it; you could just line the pictures up.

    But even once you have image files, there's about zero chance you can just replace Google Maps' tiles with your own and expect geotagged stuff to line up where it should. If you have a finite number of places of interest, you could manually locate them on each map and then try to distort each map to align, but if you expect arbitrary geolocations to need to be right, give up. Non-satellite/GPS-based maps are examples of practical cartography, not theoretical. They will be even less perfect than you think, no matter how professional they appear. Or do what we did: keep the geotag display on Google's maps, but show your historical map of the same general region side-by-side and allow the user to calculate the precise correlation in his own brain.

  • I've listened to the person in charge of archiving at the Library of Congress who handles such things, as do many other libraries. They have developed a lot of techniques for handling and dealing with large items, including restoration. I'll bet the British Museum has a similar map department.

    My bet is they have information on this at their website.

  • I dont know if this has been mentioned but Grass GIS the open source GIS program , has a georectification module that you can use to add the proper coordinates. Here is a page of the manual for your perusal. [grass.itc.it]
  • National Geographic did an article on The Mannahatta Project [nationalgeographic.com], which did the same thing -- digitized old maps, then matched up known reference points to map them into modern map overlays with GPS coordinates. It also provides some background on why this is such a cool thing to do.
  • I was a little incredulous when I discovered that I could take photos with my 10MP camera in macro mode and approach the quality of my flatbed scanner.

    If you can find a friend with a good digital SLR, and if you get your lighting all set right, you can probably just snap some pictures of it. MUCH faster than scanning. Then, you can use a stitching program like Hugin to bring all of the pics together and correct for distortion around the edges of the picture.

    If they're that old, then you might not need
  • Lots of good ideas here for doing this if you have unlimited cash. Fewer good ideas for doing it on a budget. I don't like the idea of using an SLR camera: you're going to have perspective and lighting problems which you'll need to correct in software.

    Here's my idea:
    1) Lay out map on large table.
    2) Remove top lid from $80 scanner.
    3) Flip scanner upside down, place on map.
    4) Stitch the images together, or geolocate the individual images.
    5) Profit!

  • Trying to get something usable with GPS coordinates, you will fail. If all you want is a digital representation of the map - like, say a JPEG image - this can be done but it will be difficult.

    Some insight into the process is useful. I used to work for a company involved in digital map databases. They started out digitizing maps from aerial photographs. These photographs were very high accuracy taken with large format cameras from relatively low flying aircraft. They spent years developing software to a

  • by FonkiE (28352)

    them to a library which is specialized in that:

    a) they can preserve the maps
    b) you get a scan back
    c) and some credit

    you might not realize that even though the maps might be worth something, without proper care they will slowly dissolve.

  • A good digital camera and a copy of OziExplorer will get you GPS'ing your way round Ye Olde Mappes on your computing device of choice. http://terraperfecta.com/frontmap.php [terraperfecta.com] makes calibrating the maps a point & click jobby.
  • I looked into this a number of years ago when I was dealing in old maps. The best way to digitize them by far is a large format drum scanner.

  • by Chris Pimlott (16212) on Wednesday March 10, 2010 @07:28PM (#31432564)

    I can't speak on how to get them digitalized, but once you do, look to the web to get others to help geocode and get them into shape for overlays. Put them online in a liberal CC license and invite other people to use them. Given the popularity of google maps and the community that's grown up making mashups and apps, I'd be willing to bet there already existing communities of people good at, and interested in, doing this.

    • Excellent idea, you would probably attract the attention of academics who have have knowledge of the area in question - historically - and can provide valuable input on modern locations and dimensions - since many of old maps vary in their scale internally.

  • I would build an x/y tram and mount a hd digital camera to it. Using a couple of hacks on the camera should be able to remotely trigger it from a computer program. Given stepper motors on the x/y you could control the position of the camera. This setup could be mounted over a table and the map could just lay there. Then do as others have suggested and use stitching software to put the images together.

    As part of my job I work with GIS information on a daily basis. I would say the largest issue you are going

  • Almost any map or photo will have *some* common aspect that relates to current day. Right now I am working on a project of cataloging old (back to 1937) aerial photographs of the county I live in.

    I use ESRI's ArcMap, a ruler, an excel spreadsheet and some brainpower. I pick sensible coordinates (PLSS corners make the most sense when available, as well as street intersections) and then locate them on a more-or-less current day satellite/aerial overlay in ArcMap. Once I decide on my corners, I just measure th

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