From: PO2::"QUATERNARY@MORGAN.UCS.MUN.CA" "Canadian Research in Quaternary Science" 21-APR-1995 14:56:45.99 To: Multiple recipients of list QUATERNARY CC: Subj: Line following software I posted a message nearly two months ago inquiring about the easiest way to produce a Digital elevation model from hard copy topographic maps. The object of my task is to create an elevation model of a drumlin field - like digitizing 10 000 bulls-eyes so you can see why I'm trying to find an easier way. I haven't had enough time yet to track down all the sources that I've been given but I thought I'd let everyone know what I've come up with so far. It seems that because of all the extra clutter on topo. maps such as hydrography, place names etc. the clean up process can get quite tedious. I'm still working on the problem, Though I've had some success selecting out contours (provided they are a different color than other map features) with Adobe Photoshop and saving them as a separate file. Thus, I can efficiently eliminate map clutter. As for creating vectors from a scanned raster image of the cleaned up topo map, A particular package I used (contact me personally for details) did a fairly good job at extracting vector information. It had some minor problems such as vectors jumping between contours in dense areas, but the biggest problem was that the program was extremely limited in the number of exportable file types. I recieved the following responses over the last two months and, due to popular demand, Here they are. I've eliminated the unuseful ones. Thanks to all the contributors Kent. From: "Andrew G. Fountain, Hydrologist, La kewood, CO " Call Mike Crane of the US Geological Survey's National Mapping Division (NMD) 303-236-5838. The NMD is doing alot of translation from maps to DEM's. As I understand it, they use an optical scanner which encodes the lines into digital format. I am unclear about the software end of it, but Mike or somebody in his office should know. From: John P. Hayes There is a company in New Brunswick that sells a GIS called Caris. In the package there is a semi automated raster to vector converter and a module for producing DEMS is available. You can get further information from: support@universal.ca From: sales@universal.ca (USL Marketing) Thank you for your inquiry about SAMI (Semi-Automated Map Input) Universal Systems' raster to vector conversion module. As you may already know, data collection is usually the most costly and time consuming operation of any GIS. Data needs to be collected as quickly as possible without jeopardizing accuracy when converting paper documents into digital format. An efficint method of converting large volumes of paper maps into a digital vector format is to scan map sheets and convert the resulting raster data to vector. SAMI is a computer-assisted digitizing system. It is a standalone package that works with GIS systems such as CARIS (Computer Aided Resource Information System), Integraph and ArcInfo to interactively convert scanned raster images to vector data. SAMI performs this conversion semi-automatically and facilitates fast, manual digitization of text, symbols, soundings and spot heights. It is a complete system that includes cartographic tools such as editing, symbolizing etc. SAMI is faster and more accurate than manual digitizing (on a digitizing table) when dealing with monochromatic map separates scanned in binary mode. SAMI provides an xmenu user interface which makes it as friendly as possible. While the default SAMI user interface provides you with all the necessary tools to complete a conversion, the menus can be customized to meet your individual needs. SAMI runs on several UNIX platforms and is currently being ported to the Windows environment. As well, character recognition is also being completed. The SAMI Workstation and Server module is currently offered at $2,770. Software Updates are available at $360/yr. (In the case of a multiple purchase, certain discounts apply). A formal quotation can be provided to you if required. From: "Ted Zobeck" Try contacting the folks at Rockware computer software at 800-775-6745. They have a catalog with a wide variety of geoscience related software. If anyone might have it, they might. From: wyc@crsa.bu.edu (Yecheng Wu) Hi, following is some info on R2V for Windows, automated raster to vector conversion software and getting the demo by FTP. Please let us know if you have any questions or comments on the software. R2V for Windows, a powerful raster to vector conversion system at a reasonable price. The system combines the power of intelligent automatic digitizing technology with an easy to use menu-driven graphical user interface in the Microsoft Windows environment. The system can be learned by anyone with some Windows experience within 15 minutes. R2V for Windows system is designed for the sole purpose of raster to vector conversion. You display the image on screen and you click a button. That is it! All the lines are extracted and displayed right on top of the image for you to verify and edit. Nothing else is needed to get a perfect set of vector data. The automated vector extraction algorithm is a combination of fast image thinning and intelligent vector tracking techniques and a result of long time research effort by Able Software Co. It takes less than 30 seconds to convert a typical 1024x1024 gray scale map image scanned at 200 DPI (dots per inch) on a 486 DX 33 class PC and is incredibly fast for larger images. Automatic nodes thinning function is provided for easy editing of large amount of vector data. We know it can be very painful if you don't have a good vector editor, so we have made the effort to build a smart and flexible vector editor for you to use right on top of your scanned image. Of course, vector data registration and merging are provided because we know without these functions, the vector data is simply useless. How about digitizing a number of 1936 maps drawn using pencil on papers with yellow grids? No problem. Scan the maps in 8-bit color and use R2V for Windows system. One of our users has taken care the maps with the help of R2V for Windows. Need to digitize 24x36 topographic maps? We have customers doing it on the daily basis using R2V for Windows. They will be happy to tell you how easy the job has become and how much time they have saved. R2V for Windows is currently used by many people in US and other countries. Our customers include Cornell Univ., The Catholic University of America, SPOT Image Corp., Thailand Envrionment Institute (Thailand), New Mexico State Univ., The Cadamus Group, Inc., ERSIS (Australia & Malaysia), INESC (Portugal), Neuclear Mendoza (Argentina), IMAG-CNR (Italy) and many others. System features: Input: Images in TIFF format, supports bi-level, gray scale and color images. Vector files in Arc/Info chain file format. No software limit for image sizes. Also supports SPOT satellite image format. Output: MapInfo(MIF), DXF and Arc/Info format for vector data and TIFF format for images. Support to ArcView is being added and available in the next release. More image and vector formats are being added. Vectorization: Fully automatic and fast. It extracts vector data from maps, aerial photos and even satellite images in gray scale or color. Color image classification provided to help create region maps and vectorization of color images. Options to vectorize both center line and boundary line. Vector Editing: A complete vector editor is provided using the scanned image as backdrop. Image and vector data can be zoomed in and out infinitely for easy editing. Automatic global vector generalization and thresholding functions for easy cleaning up of noisy images. Automatic chain snapping for chain merging and gap filling. Vector Labeling: Easy tools provided to label chains with different ID values. Vector layers can be created easily. Flexible display options to display chains in user specified colors. Image Processing: Vertical and horizontal flip, transpose, crop a region, smoothing using median filter, negate. Pixel values can be viewed in realtime using the Pixel Tool. Various image type conversion functions. Unsupervised classification is provided to classify multi-spectral satellite imagery and color aerial photos to generate region maps automatically. Vector Registration and Merge: Registration is performed using a geometric transformation derived from user specified control points. Multiple vector sets can be merged into a single set. Print: Any printer supported by Windows. Vector data can be printed using the maximum printer resolution. You can simply create good quality maps or drawings using R2V for Windows system. Demo: A demo version of the system is available by anonymous ftp or disk by request. (See enclosed instructions for ftp). Minimum System Requirements: PC computer with 486 or higher CPU 4 MB RAM (16 MB or higher is recommended for large images) 1 MB hard disk free space for the software. 256 color SVGA display Windows 3.1 Price: US$1895.00 (North America), US$2400.00 (International). 60% discount to educational uses. 5% sales tax if MA resident. Shipping and handling: $10 for first class mail, $20 for next day express mail, $50 international express mail. The software can be returned within 30 days of the purchase for a full refund if you are not satisfied with the performance. We offer 1 year free upgrade of major releases and unlimited technical support to our customers. To order: Make check payable to Able Software Co. (or purchase order) and send to: Able Software Co. 5 Appletree Lane Lexington, MA 02173 For more information, please contact: Able Software Co. Phone: 617-862-2804 FAX: 617-862-2640 Email: able@world.std.com Please let us know if we can be of any help. Thank you. Yecheng Wu, Ph.D. President Able Software Co. ------------------------------------------------------------- Instruction for downloading R2V for Windows demo using FTP: 1. ftp ftp.std.com 2. login: anonymous 3. passwd: your email address 4. cd /pub/r2v 5. binary 6. get r2vdemo.zip Copy the file (r2vdemo.zip) to your PC. On your PC: 1. mkdir r2v 2. cd r2v 3. pkunzip r2vdemo.zip Start Windows, and run "r2v.exe" from Windows. Use the online help to get a quick start. Sorry, I don't remember who this was from ARC does include a module to convert lines in a *scanned* image into proper map lines, which could then be converted to a DEM provided you could get access to a copy of ARC that includes TOPOGRID. I don't have much experience with scanning, but for complicated maps I think it's usually necessary to trace over the features you want on a separate sheet. In other words, you might still have to trace over 10,000 bulls-eyes. (The relevant commands for scan conversion are: IMAGEGRID and GRIDLINE). You may ultimately be better off creating a DEM directly from map sheets using a stereoscope, a process about which I know very little. From: "Rod S. March, Hyd (Glac), Fairbanks, AK " There are several ways to go about this, To best answer your question requires additional information. How big is your map? Is it one map only or do you want to acquire the hardware/software tools to do this multiple times? What software do you plan to use the digital data set in? Do you need it in a particular format? Does it need to be gridded data or just coordinates of points along the contour lines (i.e. irregularly spaced elevation data)? Do you just want a wap to electronically scale and reproduce the map, or do you want the digital data for some further analyis? For a one time only job you may be best contracting the work. Look for a local CAD (AutoCAD) dealer. Be sure to ask him about the accuracy. There are also large companies that do this kind of contract work. To do it yourself you will need either a scanner big enough to accomodate your map or a digitizing tablet. With a scanner you will need raster to vector conversion software and then a vector editing software to clean up the resulting drawing file. (Raster to vector conversion, sometimes refered to as tracing or autotracing, is an imprecise process and needs to be checked and usually corrected. Some colored maps can be problematic. If the map is large, the raster files can get really big and difficult to deal with on the average PC.) With a digitizer, you need software to control the digitizer. Most high end drawing programs like Corel Draw and Micrografx Designer and CAD programs can control digitizers and some (I know Corel does) have tracing capability. My experience is that these programs are not very good at outputting ASCII files of coordinates. From: ASHANTHA GOONETILLEKE I well understand your problem. I have just completed digitising a few maps, but fortunately I did not have to digitise so many lines. The only options that I see are, either digitising or scanning. But scanning is not so simple either, if you do not have a very clean map with no extraneous lines and other features. Also in scanning you still have to do a lot editing after scanning. I personally use a digitising package called Tosca which comes with Idrisi software. Though I have the freeware package loaded on my computer I have not had time to look at it. With Tosca what you have to do is give each line an identifier equal to some attribute (say elevation). Therefore each line is identified accordingly. I believe this is standard feature in most digitising packages. Anyway I cannot see how you can get away from the rather tedious task of having to attend to each line individually in either scanning or digitising. Sorry I cannot be of any more help to you. From: Derek Milton I understand there are a number of packages around that allow you once you have the data in a vector format to assign the values of the contours in a semi-automated manner in that the operator puts in a low value against a known contour and a hogh value agains a known high contour and the contour interval. The system then assigns the values. A group in Australia who have been working on this problem and have developed a procedure for the ARC/INFO GIS are at Uni of Tasmania. Contact is Peter.Zwart@censis.utas.edu.au. In terms of scanning and vectorising software there are many systems around that should be able to help you. If not we have here in Australia a very nice package (scanning and vectorising software that sits on a pc - compnay in Brisbane) for a commercial rate of $6,000. I can get you details if you are interested From: Derek Milton The provec system includes scanner (A0) and vectorising software and I understand there may be a uni price of about half the $6000 - these are chaep Australian dollars From: "Dennis C. Trabant, Hyd (Glac), Fairbanks, AK " Usually we obtain scale stable separates (i.e., high contrast subsets of map data) and use a commercial outfit to scan and vectorize the data. Good "vectorization" is not simple. Commercial operators use high quality and capacity software (=expensive), refreshed familiarity with its use, and have developed the error checking insights that come with experience. We have been satisfied with commercial products. From: drm7@midway.uchicago.edu (Douglas MacAyeal) My experience is with four packages: 1. NCAR's BIVAR. This package "triangulates", or Tesselates (is that the right word?), the region to be gridded using the irregularly distributed "data points" (which can be sequences of digitized contour points) as triangle vertices. (You end up with something that looks like a finite-element mesh.) After this, the grid points that fall "within" the "convex hull" of the triangulation are assigned interpolated values that are linear or quintic functions of the data values at the vertices. Problems: - Sometimes you have to trim off the edges of the convex hull to avoid the wild interpolations that occur at the edges of the domain - Lots of curvature can be added to the "field" that is based on nothing more than the vagaries of the contour-line digitizations - Slow and painful software to use, but at least it's free. 2. Argus Meshmaker Pro. This software does "input" contours that you then assign values to. The software automatically assigns the data fields to underlying finite-difference and finite-element meshes. Works very well and can do "terraced", "linear" and higher order interpolations. Argus is advertised in recent issues of EOS. Problems: - same as above - for some, it's too expensive... but I'm a zealous user so I recommend it. Also the software is a general pre-processor for lots of other numerical modelling uses. 3. Matlab. Matlab offers "interp2d" and "griddata" and other such ways of converting irregularly spaced data to a regular grid. Problems: - same as above (ain't no free lunch!) 4. Spyglass. Spyglass Transform allows irregularly distributed data to be imported and interpolated to a regular mesh. It works using "Krigging" (named after a South African mathmatician, I think) which allows each data point to determine an area of "influence" within which it will variably affect the way interpolated fields are assigned to grid points. Problems: - you guessed it... same as above Overall recommendation: You're not going to find a "magic" package out there that will give you 100% satisfaction without getting your feet wet... I've struggled for years with this issue (and have done it many times), but it's never been easy or has worked without massive subjective intervention to quell wild fields near the edges, etc. From: PO2::"QUATERNARY@MORGAN.UCS.MUN.CA" "Canadian Research in Quaternary Science" 24-APR-1995 10:13:08.84 To: Multiple recipients of list QUATERNARY CC: Subj: Re: Line following software Kent: You may wish to ILL a copy of an MS thesis completed at Lehigh University, Bethlehem, PA on the geometry and composition variations of drumlins in the Weedsport Drumlin field in New York. Doug Stahman(sp?) digitized what seemed to be hundreds of drumlins, so you may be able to extract a file or maps that have contours of drumlins with nothing else to clutter the map. Ed Evenson, his advisor and God-like mentor would have details.--john John C Gosse Geology*Geochemistry*Surface History EES-1 MS D462 Los Alamos National Laboratory Los Alamos, NM 87545 Telephone: 505 665 7728 Telefax: 505 665 3285