By Blakelee Mills on Sunday, 12 February 2017
Category: Surfer

Georeference an Image in Surfer

There are many ways to customize and enhance maps. One popular enhancement is including images such as satellite imagery, aerial photographs, or historical maps. Images provide additional information and context for the map. In order to spatially relate the image with the other geographic data sources in a map, the image must be georeferenced.

Georeferencing an image is the process of assigning real-world coordinates to each pixel of the image. The latest release of Surfer can georeference images using three or more control points. Below I will step you through some of the main georeferencing features, but for more detailed instructions on how to georeferenced an image of your own, check out our knowledge base article, How can I georeferenced (assign coordinates to) an image base map in Surfer?

When georeferencing an image, the Georeference Image window pops up as a separate window from the Surfer application. This allows you to transition from one window to the next as you verify your georeference settings are correct.

The georeference image window allows you to easily work with all aspects of your map in Surfer.

Within the Georeference Image window, you can easily navigate the image. Zoom in/out with the mouse wheel or zoom to a selected area, quickly pan the image, or adjust the view to fit the entire image in the view pane. View help text and the warp method, if one is applied, along with the pixel, geographic, and projected coordinate location of the cursor in the status bar.

The navigation tools make it easy to select, add, or delete control points. Control points match points on the image to corresponding points in real-world coordinates. Once a control point is selected, the control point table lets you view and edit the source and target coordinates.

Should you need to specify a warp methods, Surfer provides 10 options. When selecting a warp method, you’ll notice a number preceding the warp method. This number corresponds to the minimum required control points for that specific warp method.

Easily assign and edit control points to georeference the image.

Should you need to specify a warp methods, Surfer provides 10 options. When selecting a warp method, you’ll notice a number preceding the warp method. This number corresponds to the minimum required control points for that specific warp method.

  • Affine Polynomial
  • First Order Polynomial
  • Second Order Polynomial
  • Third Order Polynomial
  • Thin Plate Spline
  • Natural Cubic Spline
  • Marcov Spline
  • Exponential Spline
  • Rational Quadratic Spline
  • Inverse Distance Squared

Finally, update the map with your image that now has real-world coordinates.

Georeference your own images with the free, two week Surfer trial.

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