Line Trace Plus A Powerful Data Conversion Tool for Geographic Information Systems

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About The LTPlus Organization

At this point, the LTPlus Organization is little more than a dream. In fact, we don't even have downloadable source code yet, but ...

LTPlus was once a popular OpenSource raster editor and raster to vector conversion program for GIS data. It is very efficient. Indeed, although LTPlus is dated, we believe it is still among the best tools for this type of work. Unfortunately, LTPlus is hard to obtain. The best version only runs in VGA mode on SCO Unix. Ports to other platforms have either lacked in quality or have been proprietary.

Our goals are:

• To keep LTPlus (including source code) open and available to all
• To port LTPlus to Linux and other platforms
• To enhance LTPlus
• To act as a clearhouse for LTPlus activities

A History of LTPlus

LTPlus was designed and written by John Dabritz, who was a US Forest Service employee. LTPlus was written in C for PCs running the Xenix operating system. The first version was released in 1988 or 1989; and it was very successful. LTPlus used scanned bit maps of the manuscripts, and provided excellent raster editing and raster to vector conversion facilities. As a result, LTPlus reduced the time necessary to capture GIS data by 2/3 (as compared to manual digitizing).

The LTPlus group lead by John Dabritz continued to enhance and improve LTPlus. They also provided training and support to LTPlus users.

In 1989 David Mandel, who was a private contractor with Infotec Development Inc., proposed using LTPlus to digitize over 3000 very dense topographic manuscripts for the US Bureau of Land Management. This lead to a partnership between the Dabritz team and Mandel team. In time:

• LTPlus was ported to SCO Unix and enhanced for larger and larger images

• Tru Phan from Infotec joined the John Dabritz team as lead programmer
  Mr. Phan made major contributions to LTPlus. Unfortunately, many of his contributions are in later proprietary versions of the software.

• Infotec used LTPlus to capture data from BLM's 3000 manuscripts
  In addition to this, Infotec started a GIS data capture shop which uses LTPlus to capture data for various local and federal government agencies. The technical lead on this project was Dan Haskell, who would contribute significantly to the development of LTPlus.

• In 1992, the government dropped support for LTPlus (at ver 2.36)
  In an effort to save LTPlus, John Dabritz and his team moved to Infotec. Many of the participates wanted to keep LTPlus Open Source, and proposed funding the project by selling advertising, support, and training. However, this was a new concept at the time, and was rejected in favor of a proprietary software model. Thus, Infotec created a product called LT4X, which is a proprietary version of LTPlus with many enhancements.

• New features were added to LT4X
  LTPlus ran in SVGA mode in SCO Unix. The team moved LT4X to X-Windows and ported it to a variety of Unix platforms. They improved the documentation and added a license manager. They also added support for more projections, automatic digitizing of dashed lines and double lines, and lots of other features.

  However, many people were unhappy with the proprietary business model Infotec had adopted. Many existing LTPlus users felt Infotec was trying to steal LTPlus from the public domain. Some LTPlus developers and power users were excluded from membership in the development team, because they didn't belong to the official organization. This resulted in:
  

  • Ron and Carol Berry creating their own proprietary LT4DOS
  • Dan Haskell creating his own proprietary LTPlus for Linux
  • A port of LTPlus to NT by an inmate at the Oregon State Penitentiary
    At this time, I don't know the inmate's name or if the source code is available; but I do have contacts at the Oregon State Penitentiary and could check into this if anyone would like this.
  • Several other people doing ports of old versions of LTPlus to various platforms
    Unfortunately, some of these ports are so bad that they have hurt LTPlus's reputation.

  In the end, the official team ported LT4X to Linux. When Infotec management refused to market it they left the project. Today,

  • John Dabritz writes educational software for ImageBuilder .
  • David Mandel is Avalon Technology Group's Linux Evangelist.
  • Tru Phan is a Unix System Administrator on the IDI/BLM project.
    This project still employs a couple other key members of the BLM topo effort including David Barbour who headed the BLM/IDI production team.
  • Dan Haskell is a Unix System Administrator for GST Telecommunications
  • Ron and Carol Berry are a private consultants in Eugene, Oregon.
  • Holly Martin contributed to the LTPlus effort in many ways for many years, including working as the team's system administrator and as a major contributor or documentation for LTPlus. I don't know where she is today.
  • Many other people contributed to the LTPlus effort as well.

• Meanwhile, Infotec became part of the corporate merger game sweeping the government services industry
  • Infotec merged with Pacer Systems to become Pacer Infotec
  • Pacer Infotec merged with Intermetrics to become Averstar
    Anyone interested in LT4X should check with AverStar. I believe Averstar continues to use LT4X, but I'm not sure they market it anymore.

LTPlus features

• Scanning data conversion
  LTPlus excels at scanned image data conversion. Scanned data can be converted to vector, raster, cell, or DEM output. The program includes a number of features specifically designed to speed the processing of raw scanned images.

• Data integration
  LTPlus accepts raster and vector input from many different GIS packages. Data from existing vector themes can be imported and selectively integrated into scanned or digitized data. Imported linework and/or attributes can be copied into the current map en masse or on a point-and-click basis.

• Manual digitizing
  While it was developed for scanned data conversion, LTPlus also provides an excellent platform for manual digitizing. The program makes it easy to find and correct common digitizing errors such as shortfalls, overshoots, and isolated segments. Further, since it utilizes raster digitizing, there is no chance of double backed or duplicate lines.

• GIS specialization
  LTPlus is specifically designed to produce GIS data. Unlike CAD software, it is able to produce data that is topologically structured, geodetically referenced, and attributed. LTPlus is able to output data in any of a large number of standard GIS exchange formats.

• DEM production
  LTPlus is able to produce USGS format Digital Elevation Models (DEMs) from contour data.

• Edge matching
  Adjacent data can be viewed on screen against working data. When desired, LTPlus can snap linework along the edge to adjacent coverages. The tolerance for this snapping is user definable.

• Quality control
  LTPlus includes a rich set of commands to facilitate quality control, including both manual and automated functions. Manual functions include heads up viewing of output data over source scans; subsetting of objects based on user defined parameters; traditional hardcopy output; and a unique double attributing scheme that greatly increases the accuracy of attribute assignment. Automated schemes include the automatic location of open ended line segments, holes in the data, and free floating pixels.

• User customizable interface
  LTPlus is fully customizable. Mouse key definitions, menus choices, report formats, and digitizer settings are all under control of the user. This allows users to adapt the program to meet the needs of their work.

• Flexibility
  Data output from LTPlus has been successfully integrated into ARC/INFO, GRASS, MOSS, AutoCAD, and many other GIS and CAD systems.

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  18 supported import formats

  • asn raster from USFS FASTGRAMS
  • cell generic cell format from MTHMAP and R2MAP
  • cff USFS GSC Cartographic Feature File vector format
  • digit CERL/SCS GRASS ASCII vector format
  • dlg3 USGS vector
  • dxf AutoCAD vector
  • gis ERDAS raster
  • moss MOSS vector
  • pbm PBMPlus raw bitmap format
  • optr9 Optronics scanner format
  • ras Houston Instruments ScanCad format
  • rdef2 Raster Data Exchange Format
  • rstr A generic, bit-mapped raster format
  • rlc Ideal Context scanner format
  • rle1 Run Length Encoded raster format
  • scsgef SCS vector format
  • tan Tangent scanner format
  • xy user specified ASCII vector format

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  14 supported export formats

  • cell generic cell format (MTHMAP and R2MAP)
  • cff USFS GSC Cartographic Feature File
  • dem USGS Digital Elevation Model
  • dig ERDAS vector format
  • digit GRASS GIS vector
  • dlg3 USGS vector file
  • dxf AutoCAD vector
  • moss MOSS vector file
  • pbm PBMPlus raw bitmap format
  • rdef2 Raster Data Exchange (DWRIS, LIDES and LTPlus)
  • rstr generic raster format
  • scsgef SCS vector format
  • snap USDA Forest Service PC Snap format
  • xy User specified ASCII vector format