Image files can be images, or they can also be used as grid files. There are many ways to import an image, and which way to choose just depends what type of image you have and what you want to do with it.
- Floating Image. You can import an image as a floating image, meaning that the image is located in the plot window, and you can stretch, resize and drag it around to reposition it and it is not associated with any map. This is a great option for index map images, company logos, etc (anything that doesn't need to be georeferenced or part of a map). To import an image as a floating image, click Home | Insert | Graphic, select the image file and click Open.
- As Base layer. Base layers are map layers, meaning they have XY coordinates and can scale the image, overlay it with other layer types (e.g. contours), and drape it over a 3D surface. Images without Z values associated with them make good base layers. Base layers make great background maps for contours, post layers, watersheds or other layer types. Most aerial photography, such as Google Earth images, are used for base layers. If the image is georeferenced, loading it as a base map will preserve the map coordinates. If the image is not georeferenced, you can georeference it in Surfer to assign XY coordinates to it. To import an image as a base layer, you can either:
- Click File | Open, select the image file and click Open. Or,
- Click Home | New Map | Base, select the image file and click Open.
- As Grid. Grids are used to create many layer types, such as contours, color reliefs and 3D surfaces, and can be used in many grid operations (e.g. volume, area, isopach, etc). Many institutions, such as the USGS, offer grid files (aka raster files) in GeoTIFF format. These TIF files (or possibly other image formats) are images with Z values, and can be used as a grid file in Surfer. To use an image as a grid file in Surfer, select it whenever you are prompted for a grid. For example, to create a map from an image with Z values:
- Click Home | New Map | (grid-based layer), select the TIF or image file and click Open. If the image doesn't actually have Z values associated with it, Surfer will convert the colors in the image into Z values ranging from 0 to 255.
Updated November, 2021