File Format Export Recommendations from Surfer

Four File Format types are available for export from Surfer: grid, data, base map, and 3D. Base map formats fall into three groups: raster, vector, and metafile. Your export format choice depends on the content type and intended use. Here are some common scenarios with recommended export formats.

Grid Files

Grid files (e.g. ADF, ASC, DEM, GRD) consist of grid nodes or cells located at specific x,y coordinates, each with corresponding z values.

Surfer supports grid files with evenly spaced nodes or cells, although some may have uneven spacing. The grid file defines x, y limits, node spacing, and null values, and maintains consistent information. Grids can be saved in Surfer to create contours, watersheds, or perform calculations. The x,y, and z data remain constant across formats, so choose a compatible format. If you primarily use Surfer, save grids in its default format. If you use ArcMap, select a supported ESRI format (ADF, ASC, or FLT).

For guidance on creating grid files in Surfer, refer to the Surfer Gridding Training Video.

Data Files

Data files (e.g., CSV, DAT, TXT, XLSX) are used to store raw data, including important information such as x, y coordinates, z values, and labels. 

You can save Surfer worksheets without altering their content. If you're working with large datasets, storing them in XLS or XLSX formats may result in data loss. XLS can handle up to 65,536 rows and 256 columns, whereas XLSX allows for a much larger capacity of 1,048,576 rows and 16,384 columns!

Base Maps

The three primary types of base map files are raster images, vector files, and metafiles.

Raster maps, which encompass image maps and 3D surfaces, are in raster format. In contrast, lines and text utilize vector format, which allows for quality preservation during resizing. Moreover, vector files tend to be smaller than raster files. Metafiles do not include spatial references, coordinate system information, or attribute/Z values. When used in Word or PowerPoint or re-imported into Surfer, metafiles can be broken down to access their individual components.

Base Map: Raster Image Files

Raster images (e.g. JPG, GeoTIFF) show exactly what appears on the screen and are great for sharing maps in emails, reports, presentations, or publications. These files allow georeferencing in Surfer but do not permit editing individual elements like line styles and text; color attributes can be adjusted with image processing software.

All formats export an image from your Surfer project, with choices varying mainly by compression, transparency, or publication requirements. Each format enables you to set pixel size, resolution (dpi/ppi), document size (in or cm), and color formats, and can include spatial reference information (real-world XY coordinates).