|Title||Tablet PC-based data capture and attribution of geolosical features using custom ArcMap tools|
|Author||Paul, D; Viljoen, D|
|Source||32nd Annual Yellowknife Geoscience Forum, abstracts of talks and posters; Northwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume vol. 2004, 2004 p. 58-59 Open Access|
|Alt Series||Earth Sciences Sector, Contribution Series 2004161|
|Publisher||Northwest Territories Geoscience Office|
|Meeting||32nd Annual Yellowknife Geoscience Forum; Yellowknife, NWT; CA; November 16-18, 2004|
|Media||paper; on-line; digital|
|Subjects||general geology; Science and Technology; computer mapping; software|
|Released||2004 11 01|
|Abstract||Custom tools were developed at the Geological Survey of Canada in Ottawa to facilitate digitizing features on paper maps using ESRI's ArcMap software. |
Traditionally, this conversion process involves
tracing geological features onto several mylar overlays. Using registration tics, the mylars are then scanned, georeferenced and the linework are vectorized. Disadvantages of this method include inaccurate registration of features between mylars, and
the raster to vector conversion usually results in errors that need to cleaned to create topologically sound data. This data cleaning is very time consuming.
In our Tablet-PC based method, a scanned georeferenced image of a paper map is used as a
backdrop for on-screen sketching and simultaneous attribution of features using custom ArcMap tools. These tools include a LayerAttributer tool, for coding point, line and polygon features, and DigSym, a tool for capturing oriented point features
like geological structures. These tools accurately capture on screen sketches into attributed shapefiles or feature classes in personal geodatabases. The attribute values for each feature type are user-defined and stored in an XML document. Within
the LayerAttributer and DigSym tools, their associated XML files are used to populate drop-down picklists in ArcMap. Once a feature is drawn as an ink-sketch, it is converted to a vector feature and automatically coded with the attribute value
selected in the picklist.
Digital conversion of paper geological maps is a tedious and time-consuming process. The benefits of using ink technology (Windows XP Tablet Edition) and a Tablet PC are the speed and ease with which lines and points are
captured. Tablet PC's are more ergonomic than a traditional workstation set-up because they allow the user to sit in a comfortable sketching position. The paper source map is much more useful stored as a digital georeferenced image that can be used
as a digital layer with the newly captured geological data and any future interpretations of that data. Finally, the Layer Attributer and DigSym tools enable features to be automatically attributed as they are drawn. The standard symbolization tool
in ArcMap allows the user to see what information has been captured and check the attribution graphically.