What File Format Should I Export from Surfer?

Surfer supports exporting to many different file formats. When exporting data from Surfer for use either in another software package (either another Golden Software package or a third-party application), for inserting into a publication, or for any other purpose, the multitude of supported file formats can be confusing. It may not always be clear when you should be using the Golden Software file types (e.g. BLN, GSB, GSI, ...) or another file format (e.g. DXF, SHP, MIF, ...).

There are three main types of files you can export or save from Surfer: grid files, data files, and base map files. The base map file formats can be further subdivided into three types: raster image, vector, and metafile formats. Which format you choose to export depends on what you are exporting, and what you want to do with the exported data. All file formats are designated by type in the Supported File Formats article on the support website.

1. Grid Files (e.g. ADF, ASC, DEM, GRD)
2. Data Files (e.g., CSV, DAT, TXT, XLSX)
3. Base Map Files
3a. Raster Image     (e.g. BMP, JPG, GeoTIFF, TIF)
3b. Vector     (e.g. E00, DXF, KML, MIF, SHP)
3c. Metafile     (e.g. EMF, WMF)

1. Grid Files

Grid files contain grid nodes or grid cells at x,y locations, and these nodes/cells have specific z values associated with them. The grid files Surfer supports have evenly-spaced grid nodes/cells, though there are grid files that have uneven spacing. The x,y limits in map units, the grid spacing, and null values are all defined in the grid file.

There is not much variation in the information saved to these types of files. You could save a grid from Surfer to create contours, watersheds, or other map types in Surfer or other applications, or perform other grid calculations such as math or volume operations. The x, y and z information is the same in all grid formats, so the format you choose depends on the supported file formats of the program in which the grid will be used. For example, if you work primarily in Surfer, save grids in the default Surfer grid file format. If you want to bring the grids into ArcMap for display, save the grids in one of the supported ESRI grid formats (e.g. ADF, ASC, or FLT).

Information about creating grid files in Surfer can be found in the Surfer Gridding Training Video.

2. Data Files

Data files contain raw data. These can be Excel spreadsheets or ASCII data files. They can contain x,y information along with z values, labels, or other data.

Again, there is not much variation as all of the data files contain the same basic information. You can save a data file from the Surfer worksheet in many different formats, including CSV, DAT or XLSX. No matter the format, the data that is saved will be the same. The exception is Excel files. If you have many thousands of rows of data and save to an XLS or XLSX file format, some of the data may be lost, since the Excel formats are limited to a certain number of rows and columns:

• XLS file format is limited to a 65536 rows and 256 columns
• XLSX is limited to 1,048,576 rows and 16,384 columns

3a. Base Map: Raster Image Files

Raster images are images of exactly what you see on the screen. This type of file is a good option for sending a picture of the map to a colleague, inserting the image into a report or presentation, uploading the image to a website, or sending the image to a publication for print. This is also a good choice if you need a georeferenced image to overlay with other map types either in Surfer or other applications. Normally individual elements are not editable in raster image file formats. So, line styles, line widths and text properties are not editable. Some options, such as color, are editable using image processing software.

Similar to grid and data files, there is little variation in the actual content of these files. A picture of what is in your Surfer project file is exported. The main differences between formats are some of the format-specific options. Which format you choose depends on if you need compression or background transparency, or what format you are required to provide (if you are going to use it in another application or for publication).

All the image export formats support options for setting the size in pixels, the resolution (dpi/ppi), the document size (in or cm), and the color format for the exported image. In addition, all image formats have the option to include spatial reference information (real world XY coordinates and coordinate system).