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 four main types of files you can export or save from Surfer: grid files, data files, base map files, and 3D 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)
Surfer grid files contain evenly-spaced nodes of x,y,z values, and can be used to create contour maps.
2. Data Files
(e.g. CSV, DAT, TXT, XLSX)
Data files, like XLSX and TXT files, can be used to create maps in Surfer
3. Base Map Files  
    3a. Raster Image
    (e.g. JPG, GeoTIFF, TIF, PDF)
Raster image files like JPGs and PNGs can be used to create base maps in Surfer.
    3b. Vector
    (e.g. DXF, KML, MIF, SHP, PDF)
Vector files like DXFs and SHPs can be used in Surfer to cretae base maps or grid files.
    3c. Metafile
    (e.g. EMF, WMF)
Metafiles like EMFs and WMFs can be used to create base maps in Surfer.

4. 3D Files

(e.g. 3D PDF, VRML, STL)

Create 3D visualizations in Surfer and export them to 3D file formats such as VRML and 3D PDF

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).


3b. Base Map: Vector Files

Vector files contain separate object entities such as polylines, polygons, points, text, and images.

There is a wide range of vector format types available. Each type contains different information. For example, some formats contain color information, while others do not. Some contain coordinate information, while others do not. Some formats support text and imagery, and others do not. The format you ultimately export depends on what type of data you need and what other application you are going to use the file. Some vector export formats support the option to include spatial reference information.

3c. Base Map: Metafiles

There are two additional formats that are actually a blend of raster and vector data. These are the metafile formats, EMF (Windows Enhanced Metafile) and WMF (Windows Metafile). A metafile format is an excellent format to choose when inserting maps into reports and presentations. The inserted image looks almost identical to the appearance of the map in Surfer.

Raster maps (e.g. image maps, 3D surfaces) and images are exported in raster format, while lines and text are exported in vector format. After inserting the metafile into another application, there is no degradation in the vector objects when the image is resized. The file is also typically smaller than raster files, since objects stored in vector format take up less space.

There is no spatial referencing or coordinate system information, and there are no attributes or Z values exported to a metafile format. When you insert a metafile into Word or PowerPoint, or import it back into Surfer, you can break it apart to access the individual items in the file.


4. 3D Files

3D files contain information to view the model in true 3D in other programs. This could be a 3D PDF, to be given to clients and viewed in other common applications like Adobe Acrobat. Or it could be saving a grid file as an STL file to be printed using a 3D printer. There are some options when exporting to a 3D file, such as setting the vertical exaggeration (e.g. used when the XY units are not the same as the Z units) and quality.


Common Scenarios

Based on the information above, here are some common scenarios and the recommended export formats.

Reason for Export
Recommended Export Format
Publication on the web SVG or PNG
Publication in print TIF (at least 300 dpi) or vector PDF
Insertion into PowerPoint or Word EMF
Use in GIS (and you want attributes) SHP or MIF
Use in GIS (and you want attributes and colors) MIF
Use in GIS/CAD (and you want colors) DXF or MIF
Use in GIS/CAD (and you want Z values of contour lines) DXF or SHP
Use in other Golden Software applications GSI
Use in Google Earth KML or KMZ
Use as a background image GeoTIFF or GeoPDF
Print to a 3D printer STL or VRML
Show 3D model to clients or coworkers 3D PDF

Not all your needs may be met with a single file format. Even in one of the common scenarios above, another format may be more suitable to your needs than the recommended one. For more information, peruse file types in the File Format Chart help page, and click on individual file types to open pages containing more detailed descriptions. You are also welcome to contact us with any questions.


Updated November, 2021

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