Contour Digitizing

Many excellent quality geophysical surveys were flown prior to the digital era and were compiled manually. These include regional surveys, often funded by government agencies, as well as many magnetic/electromagnetic/spectrometer surveys, privately acquired for mineral and oil exploration. The quality and availability of this data is often overlooked due to the fact that it is not amenable for use with modern, computerized analysis and presentation techniques.

A service to generate high-resolution digital gridded and profile data from manually drawn contour maps has been developed by Scott Hogg & Associates Ltd. The process incorporates digital scanning and line-following tools together with specialized gridding techniques that preserve all of the detail available.

An Example

The image to the right shows the original hand-drawn magnetic contour map. After the map is scanned, the contours and flightpath are digitized using line-following software.

The digitized contour data is then taken through a proprietary process that produces a digital grid, with all the original information intact (shown to the left.) The flighpath is then threaded through the grid to create a profile database.

Now in digital form, the data may undergo modern filter and other processing techniques. The image to the right shows a magnetic residual grid calculated from the newly generated total field grid.

The above example is taken from an airborne magnetic survey in the State of Goias, Brazil.

For information on the availablity of Brazilian data, please click here.