Surfer Versions 5 and 6 FAQ

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This document covers frequently asked questions about Surfer versions 5 and 6, running under Windows 95, 98, NT 4, 2000, Me, and XP. 

• For version 8, see Surfer FAQ for Version 8.

• For version 7, see Surfer FAQ for Version 7.

• For questions about older DOS versions of Surfer or running Surfer under older versions of Windows, contact surfersupport@goldensoftware.com.

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Q1. How can I get the latest version of Surfer?

Q2. How do I convert from UTM coordinates to latitude/longitude?

Q3. I am using Windows 3.1x or Win95/98 and I want to plot my map on very large paper, but Surfer only accepts paper sizes less than 32.76 inches. How can I bypass this limitation?

Q4. How can I simultaneously print several copies of the same plot if there is no place to specify the number of copies in the Print dialog box?

Q5. My copy of Surfer version 6 has trouble recognizing long file or directory names that are supposed to be allowed under Win95/98 or NT. What is going on?

Q6. When in My Computer or Explorer and I click on a filename with the SRF extension and there are spaces in the directory or filename, Surfer cannot find the file.  Is there a way to add this capability to Surfer?

Q7. I am trying to install a copy of Surfer for Windows version 5 on Windows 95. It appears to copy all the files to my hard drive, then hangs after issuing the message: “Setup was able to modify the WIN.INI”. What is wrong?

Q8. How do I create a vector plot using Surfer 6?

Q9. My contours should be limited by some type of barrier, such as the shoreline of a lake or a fault line. If I just grid my data as it is, Surfer incorrectly extrapolates contours beyond this boundary. How can I confine my contour lines to a specific area?

Q10. I want to reshape individual contour lines, but do not want these changes to affect all the surrounding data. Can I do this?

Q11. I have carefully created a map at the appropriate scale and with the map limits I desire. Whenever I try to overlay a new map with the existing map, Surfer changes the scale and limits to the new map, which is not what I want. Is there a way to overlay a new map onto an existing map without changing the scale and limits that I have already set?

Q12. I want to create a file containing the X, Y and Z coordinates of my contour lines. How can I do this?

Q13. My data is in curvilinear (cylindrical or spherical) coordinates. How can I get it into a format that Surfer can use?

Q14. Can I control Surfer from Visual Basic or another programming environment?

Q15. I have successfully gridded my data; however, my color-filled contour map shows no contour lines. What is wrong?

Q16. How can I change the Surfer grid file blanking value to 0?

Q17. How can I print a map that is zoomed in on a smaller area?

Q18. When I overlay two base maps, how do I tell which is which?

Q19. When overlaying base maps in a script how do you assign a label to them so that when you edit or break apart one of them you don't have to randomly select base maps?

Q20. I've created a map with grid lines parallel to the axes, but the grid lines stop before reaching the opposite axis.

Q21. I used the drawing tools to add lines, rectangles and text to my map, but these objects don't move when I rescale the map with the Map | Scale menu.

Q22. I recently downloaded GTopo30 DEM files from the USGS web site, but Surfer fails to recognize the DEM file as valid. How can I load these files into Surfer?

Q23. I would like to convert my grid or DEM file to an ASCII XYZ file, but that file type is not listed in the Grid | Utility | Convert menu in Surfer.

Q24. I want to blank the grid nodes outside several polygons on a map, but the entire map gets blanked, resulting in a horizontal planar grid.

Q25. I want to use a BLN blanking file to blank the area outside a polygon, but when I load the BLN file as a base map, I can only fill inside the polygon.

Q26. In a linear variogram model, how is the scale calculated?

Q27. I have created a postmap, but the posts are rather close together and some of the labels overlap each other. Is there a way to manually move them around?

Q28. How do I change the map coordinates in a DXF file within Surfer?

Q29. Is there a way to calculate the Z value in the grid [.GRD] file at particular XY locations?

Q30. How are the residuals calculated when the desired location does not fall on a grid node?

Q31. How can I run Surfer minimized in a script?

Q32. How can I load Surfer with a different SET file in a script?

Q33. How can I load a new SET file in a script once Surfer is running?

Q34. Surfer does not calculate the minimum and maximum X (or Y) in the grid file correctly when I grid my data. How can I change this?

Q35. What gridding method should I use to grid my data file?

Q36. What's the best method for gridding a data set consisting of digitized contours?

Q37. What are the meanings of the parameters in a LVL file?

Q38. How do I use the USGS 7.5 minute DEM data in the SDTS format?

Q39. Does Surfer work with Windows 98, 2000, and XP?

Q40. I get the error "Too Many Points" when I try to display a contour map.  I see a gap in the color fill when I try to overlay a filled contour map on a surface map.  How can I resolve this problem?

Q41. Using the Surfer Scripter, how do I set the width and height of an exported bitmap (GIF, TIF, BMP, PCX, JPG) with FileExport( )?

Q42. How can I create my own symbols for use in Surfer, Grapher, and MapViewer?

Q43. I have invested in Adobe typefaces.   How do I use these type faces with Golden Software products?

Q44. How can I calculate the area between contours?

Q45. When I grid my data file using kriging, it produces a grid file with negative Z values, or with values that go beyond the Z limits in my data file.  How do I change this?

Q46. How can I make the symbols in the classed post legend the same size as on the map?

Q47. How can I enter a "null value" (a value that is ignored when gridding or performing mathematical calculations) into the Surfer worksheet?

Q48. How do I display the scale bar in miles or kilometers when the XY coordinates are in degrees of latitude and longitude?

Q49. When I change the map limits on a post map, data point labels disappear for points that are on the edges of the map but inside the limits.  How can I display these labels?

Q50. I am having a problem printing ("Out of global memory" error, only a portion of the map prints, etc.).

Q51. Are there any additional scripts available for download.

Q52. How can I round data values in the worksheet?

Q53. Where do I find my serial number?

Q54. Is technical support free?

Q1. How can I get the latest version of Surfer?
A. Minor updates (e.g. version 7.00 to 7.02) may be downloaded for free if your serial number is registered.  To register, enter the requested information on the Register Software page including your e-mail address, and add a note in the Comments field to Attn:  Surfer Support indicating that you would like to download the latest version.  If you have already registered, send a message to surfersupport@goldensoftware.com with your serial number.  Once your serial number is verified, we will send you download instructions.

Major upgrades (e.g. version 6 to version 7) cost US$139 plus shipping.  Refer to the order form for more information.

Q2. How do I convert from UTM coordinates to latitude/longitude?
A. Didger 2 from Golden Software converts data and boundary files between 21 different projections, including Unprojected Latitude/Longitude and UTM.

Q3. I am using Windows 3.1x or Win95/98 and I want to plot my map on very large paper, but Surfer only accepts paper sizes less than 32.76 inches. How can I bypass this limitation?
A. The 16-bit versions of Windows use a coordinate system that limits the maximum paper size. The 32-bit versions of Windows (NT) do not have this limitation. There are several ways to work around the problem:

• Design your map at half scale, and print at 200% scale.

To print a map on 24"x 40" paper at a scale of 1.0 in. = 1.5 Map units, designate the paper size in Surfer as 12"x 20", and design the map at half scale (1.0 in. = 3.0 Map units). When printing the map, specify 200% scale in the Print dialog box. The map is printed at a scale of 1.0 in. = 1.5 Map units on 24"x 40" paper.

• Use a text editor to add a new line to the Surfer INI file* that reads:

LogPerInch=500

Add the line to the [Settings] section of the surfer.ini file.

Save the changes, and restart Surfer. This method doubles the maximum paper size to 64 inches, but it also doubles the size of all SRF files created without the LogPerInch=500 setting.

Surfer 8 eliminates this restriction.

Q4. How can I simultaneously print several copies of the same plot if there is no place to specify the number of copies in the Print dialog box?
A. If you are running Win95/98 or NT 4, choose Print Setup from the File menu. Select the appropriate printer and click on the Properties button. There may be a place to specify the number of copies under the Paper tab.  If you are running Windows 3.1x or Windows NT 3.51, double click on the Control Panel icon located in the Main group of the Program Manager. Double click on the Printers icon and select the driver that you wish to print to. Press the Setup button. Many printer drivers provide an option for specifying the number of copies at the bottom of this dialog box. 

Q5. My copy of Surfer version 6 has trouble recognizing long file or directory names that are supposed to be allowed under Win95/98 or NT. What is going on?
A. Long file names were added to version 6.03. Please contact Surfer Technical Support by e-mail with your Surfer 6 serial number for update information.  (You may also contact us by telephone, fax, or regular mail.) 

Q6. When in My Computer or Explorer and I click on a filename with the SRF extension and there are spaces in the directory or filename, Surfer cannot find the file.  Is there a way to add this capability to Surfer?
A. In Win95/98 and NT, open the file surfer32.reg in a text editor and change the following lines:

HKEY_CLASSES_ROOT\Surfer\shell\print\command = C:\SURFER6\surfer32.exe /p "%1"
HKEY_CLASSES_ROOT\Surfer\shell\open\command = C:\SURFER6\surfer32.exe "%1"

to add quotes around the "%1" at the end of each line.  Your path for the surfer32.exe file may be different than the default path shown above.  Save the changes, then double-click on the surfer32.reg file in Windows Explorer to add the changes to the Windows Registry.  (Note:  Windows 3.1 does not support long file names or spaces in file and directory names.)

Q7. I am trying to install a copy of Surfer for Windows version 5 on Windows 95. It appears to copy all the files to my hard drive, then hangs after issuing the message: “Setup was able to modify the WIN.INI”. What is wrong?
A. Due to a bug in the way Windows 95 handles the setup routines of older software, the Surfer 5 setup was unable to create the necessary icons on your Windows 95 desktop. The installation was successful in all other respects. You can create an icon manually by adding a shortcut to the Surfer executable file located in the winsurf subdirectory. Surfer 5 should run fine once you have created this icon. You will need to upgrade to Surfer version 7 to take advantage of the 32 bit capabilities of Windows 95, including increased speed and better stability.

Q8. How do I create a vector plot using Surfer 6?
A. To create a vector plot, you must first create a data file containing X,Y coordinates, angle and magnitude columns. Angular data should be in degrees, where a positive value rotates the symbol counterclockwise. If you use an arrow in the Default Symbols symbol set as your symbol, 0 degrees rotation will result in an arrow pointing up. In a Surfer plot window, choose the Post command from the Map menu. In the Worksheet Columns group, specify the columns containing the X and Y coordinates, and the column containing the angle data. Click the Default Symbol button and choose an arrow symbol from the Symbol palette. Click OK and your selection appears in the Default Symbol button. In the Symbol Size group, select the Proportional option, and click the Scaling button. Select the Linear Scaling Method option, and specify the worksheet column containing the magnitude data. If you want, you can specify the Symbol Height corresponding to specific data values. Click OK twice, and a vector plot of your data is created.

A vector map type has been added to Surfer 7.

Q9. My contours should be limited by some type of barrier, such as the shoreline of a lake or a fault line. If I just grid my data as it is, Surfer incorrectly extrapolates contours beyond this boundary. How can I confine my contour lines to a specific area?
A. In this case it is necessary to introduce data into your X,Y,Z data file so the contours are forced to remain inside the boundaries. To do so, you need to have the coordinates defining the boundary. This information is often stored as a BLN file. If you do not have a BLN file, you may use Surfer's digitize feature to define the coordinates of the boundary.

Choose the Worksheet command from the File menu and open the data file containing the data you wish to grid. Move to the bottom of the file by pressing the END key. Make sure that the active cell is in Column A. Choose the Merge command from the File menu, and select the file containing the boundary information. Click OK and the boundary data will be added to the end of the data file. If you used a BLN file, delete the row containing the BLN header. In Column C, specify the Z data value to be associated with the boundary. In the case of a lake shoreline where your data measures water depth, the value zero should be assigned to each of the X and Y coordinates along the boundary. Save the data when you are done. Then create a new grid from this data file, and the barrier will control the location of the contour lines on the map.

You may want to upgrade to Surfer 7 to avoid having to use this work-around.

Q10. I want to reshape individual contour lines, but do not want these changes to affect all the surrounding data. Can I do this?
A. Choose the Grid Node Editor command from the Grid menu, and open the grid file you wish to modify. This opens a window containing a contour map of your grid file. There is a small cross at every grid node. Click on a grid node you wish to modify. At the top of the Grid Node Editor window, Surfer displays the X,Y and Z coordinates of the selected grid node. You can alter the value of a grid node by typing in a new Z value into the Z box at the top of the window. This will not affect the Z values of the surrounding grid nodes. Be sure to save the modified grid file when you are finished with the Grid Node Editor.

Q11. I have carefully created a map at the appropriate scale and with the map limits I desire. Whenever I try to overlay a new map with the existing map, Surfer changes the scale and limits to the new map, which is not what I want. Is there a way to overlay a new map onto an existing map without changing the scale and limits that I have already set?
A. Surfer 6’s SET files allow users to override defaults such as this. SET files are described in detail starting on page 19-7 of the Surfer manual. This procedure describes the steps necessary to override the defaults which reset the scale and map limits every time you overlay a new map. Before you create or open the map containing the scale and limits that you wish to keep, choose Default Settings under the Preferences option of the File menu. Scroll to the Map Scale and Map Limits section near the bottom of the SET file. Enter an asterisk (*) next to every parameter in the Map Scale and Map Limits section. For example, the start of the first line in the Map Limits section should read: xMinLim* =. This tells Surfer to automatically add the parameters you choose to the SET file. Click on the Save button and save the file using some filename other than Surfer.Set (i.e. Limits.Set). Click OK to return to the plot window. Now create or open a map containing the proper limits and scale. You need to choose the Map Limits and Map Scale commands at least once to force Surfer to write those parameters to the SET file. Once you have done this, return to the SET file by choosing Default Settings under the Preferences option of the File menu. Note that Surfer has written in all the relevant parameters under the Map Scale and Map Limits sections. Now delete the asterisks from the SET file parameters. Click the Save button to save the SET file using the same filename, and click OK to return to the plot window. All maps that you create while this SET file is active will have the map limits and scale that you specified by default. These parameters will no longer be reset when you choose overlay maps. To return to the original SET file, simply click on the Load button at the Default Settings dialog box or exit and restart Surfer.

Q12. I want to create a file containing the X, Y and Z coordinates of my contour lines. How can I do this?
A. We have written a GS Scripter program ( cont2xyz.bas ) which creates a file containing the X,Y and Z coordinates of your contour lines.   This program is available for download from our Scripts Library.

Surfer 7 has the ability to export contour lines to a 3D DXF file.

Q13. My data is in curvilinear (cylindrical or spherical) coordinates. How can I get it into a format that Surfer can use?
A. We have written a GS Scripter program ( crv2xyz.exe ) which can convert from cylindrical or spherical coordinates into X,Y and Z data.   This program is available for download from our Scripts Library.

Q14. Can I control Surfer from Visual Basic or another programming environment?
A. Yes.  Surfer can be completely controlled by any Automation-capable programming language, including Visual Basic, Visual Basic for Applications (that ships with the Microsoft Office suite), or the Scripter programming language included with Surfer.   Scripter is very similar to VBA.  Most modern compilers include some facility for calling Automation-capable applications, including Visual C++.  Check your language documentation for Automation or Active-X Automation support.

Q15. I have successfully gridded my data; however, my color-filled contour map shows no contour lines. What is wrong?
A. Check to see if at least one of the contours is within the range of your gridded data. For example, a contour map will appear blank if there are contours of 0 and 100 while the gridded data ranged from 20 to 80. You can also create an additional contour (such as 50 in this example) with the same color as the level below it (0 in this example).

Q16. How can I change the Surfer grid file blanking value to 0?
A. Convert the grid file from binary to ASCII, and use a text editor to search for the blanking value and replace it with 0.

Step by Step Instructions:

1. In Surfer 6 choose the Grid | Utility | Convert menu to display the Open Grid dialog box.
2. Specify the name of the grid file to be converted and press OK.
3. In the Save Grid dialog box, type in a new grid file name and make sure the Save File As Type is set to GS ASCII (*.GRD).
4. Open the ASCII GRD file in a text editor or word processor.
5. Search for the blanking value 1.70141E+038 and replace it with 0.
6. Save the file in an ASCII TXT format with the GRD extension.

Q17. How can I print a map that is zoomed in on a smaller area?
A. Surfer 6: Choose the Map | Limits menu and specify the x and y minimum and maximum coordinates of the area of interest. Choose the Map | Scale menu to specify the desired size of the map.

Surfer 5: Use the Map | Scale menu to make the area of interest fill the page. Since the maximum page size is 32 inches for this version of Surfer, you may need to use the File | Page Layout menu to specify a smaller page size to fit the area of interest. Then use the File | Print | Truncate menu to clip the printout to the edge of the page.

Q18. When I overlay two base maps, how do I tell which is which?
A. Perform the following steps:

1. Select a base map with Ctrl+Click (hold the Ctrl key down when clicking button 1 on the mouse *usually the left button*).
2. In the lower left corner of the window, the status bar should display "Map: Base". 
3. Choose the Edit | Object ID menu to specify a name.
4. Repeat for other maps in the overlay.

Q19. When overlaying base maps in a script how do you assign a label to them so that when you edit or break apart one of them you don't have to randomly select base maps?
A. There are two steps to naming your maps,

1. to name the "frame" or "container" that holds the map and axes, and
2. to name the "contents", i.e. the actual maps.

When you click on a map interactively in Surfer, the status bar in the lower left corner of the window will report the map frame to the left of the colon and the map contents to the right of the colon, as in "Map: Base".

In a script, you can assign the name of the frame when you issue the Surf.MapLoadBaseMap() command:

Surf.MapLoadBaseMap("c:\surfer6\demogrid.bln", ID="Frame1")

The next step is to select the base map contents and assign a new ID to the contents:

Surf.Select("Frame1:Base")
Surf.EditSetObjectID("Base97")

Note that the space after the colon is omitted in the script. If you stop the script here, the ID displayed in the status bar will be:  

"Frame1: Base97"

When you overlay two maps, the frame of the oldest map is used to hold both maps, and the second frame is deleted.

Q20. I've created a map with grid lines parallel to the axes, but the grid lines stop before reaching the opposite axis.
A. If you extend the axis limits beyond the minimum and maximum x and y limits of the data set, the grid lines will stop at the limits of the data.

• For a post map: Add data points to the data file corresponding to the desired lower left and upper right corners of the map.
• For a contour map, image map, or shaded relief map: Consider changing the limits when gridding to correspond to the desired axis limits.
• For a base map: Edit the base map file to include points or lines at the lower left and upper right corners.
• For any map: Overlay a post map with points at the lower left and upper right corners.

Q21. I used the drawing tools to add lines, rectangles and text to my map, but these objects don't move when I rescale the map with the Map | Scale menu.
A. To get objects to move with a map, they should be converted to "map" objects, i.e. objects with map coordinates and overlain on existing maps.

• Points can be digitized to a DAT file using the Map | Digitize menu to digitize the points, then saved with the .DAT extension. Display these points with a post map. Select both maps and use the Map | Overlay Maps menu to combine the maps.
• Text can be saved in a DAT file after digitizing the location of the text using Map | Digitize. Click on the map to record the desired location of the text, type a comma after the XY coordinate in the DIGIT.DAT window, and type the text surrounded by double quotes. When you are done digitizing the text locations and adding text, save the file as a DAT file. Load the DAT file as a post map and overlay with the existing maps.
• Lines can be converted to a BLN file using the Map | Digitize menu to digitize the points, then adding the BLN header in the DIGIT.DAT window and saving to a BLN extension. Load the BLN file as a base map and overlay with existing maps.
• If you know the coordinates corresponding to objects on screen, you can export the drawing as a DXF file with map coordinates.  The Export DXF dialog box lets you specify page coordinates under the Page Rectangle heading and corresponding map coordinates under the DXF Rectangle heading. Load the DXF file as a base map and overlay it with existing maps.

Q22. I recently downloaded GTopo30 DEM files from the USGS web site, but Surfer fails to recognize the DEM file as valid. How can I load these files into Surfer?
A. GTopo30 DEM files are in a different format than the original USGS DEM files, even though they both use the .DEM file extension. Download a free conversion program from Golden Software, and follow the instructions contained within the file to convert the GTopo30 file to a Golden Software GRD file suitable for use with Surfer.

Surfer 7 can load these files without the conversion process.

Q23. I would like to convert my grid or DEM file to an ASCII XYZ file, but that file type is not listed in the Grid | Utility | Convert menu in Surfer.
A. Click on the drop down arrow in the "Save File As Type" box and scroll down to select the "ASCII XYZ (*.DAT)" type.

Q24. I want to blank the grid nodes outside several polygons on a map, but the entire map gets blanked, resulting in a horizontal planar grid.

A. It may be that the area outside polygon A is inside polygon B, and vice versa, causing the entire map to be blanked. Combine the two polygons into a single polygon, and repeat the first vertex of the first polygon at the end of the second polygon to create a single combined polygon. Change the header of the combined polygon to reflect the total number of vertices in both simple polygons, plus the repeated first vertex. If you load the combined polygon as a base map, a line is drawn back to the first vertex, so you may need to keep both versions of the BLN available, the separate polygons to use as a base map, and the combined polygon to use for blanking purposes.			Blanking the area outside multiple polygons blanks the entire grid.
.
two separate polygons 5 0 'Polygon A 1.0 1.0 1.0 2.0 2.0 2.0 2.0 1.0 1.0 1.0 5 0 'Polygon B 3.0 3.0 3.0 4.0 4.0 4.0 4.0 3.0 3.0 3.0	one combined polygon 11 0 'Polygon A 1.0 1.0 'x1 y1 1.0 2.0 2.0 2.0 2.0 1.0 1.0 1.0 3.0 3.0 'Polygon B 3.0 4.0 4.0 4.0 4.0 3.0 3.0 3.0 1.0 1.0 'repeat x1 y1		Editing the blanking file to combine the polygons resolves the problem.

Q25. I want to use a BLN blanking file to blank the area outside a polygon, but when I load the BLN file as a base map, I can only fill inside the polygon.
A. The Map | Base Map menu does not have the ability to fill outside a polygon, but there are other methods to consider:

Modified file in BLN format

11
0.0 0.0		"(x1,y1)"
9.0 0.0
9.0 7.0
0.0 7.0
0.0 0.0		"Repeat (x1,y1) to close outer polygon."
1.0 1.0		"Start internal polygon.
2.0 1.0
2.0 2.0
1.0 2.0
1.0 1.0		"Close internal polygon.
0.0 0.0		"Repeat (x1,y1) to close outer polygon."

The BLN format draws the connecting line from the internal polygon to the repeated (x1,y1) point at (0,0). Set the line style to Invisible for this base map, or use the BNA format, which does not draw the connecting line:

Modified file in BNA format

"","",11
0.0 0.0
9.0 0.0
9.0 7.0
0.0 7.0
0.0 0.0
1.0 1.0
2.0 1.0
2.0 2.0
1.0 2.0
1.0 1.0
0.0 0.0

Q26. In a linear variogram model, how is the scale calculated?
A. The scale is calculated as the variance of the data points.

The variance is calculated as follows:

where "N" is the number of data points.

The other parameters are calculated as follows:

default length = search radius 1 = (diagonal of xy limits) / 2
default anisotropy = search radius 1 / search radius squared.
default anisotropy angle = search ellipse angle
default error variance = 0
default micro variance = 0

Q27. I have created a postmap, but the posts are rather close together and some of the labels overlap each other. Is there a way to manually move them around?
A. The best thing that you can do is isolate the labels that overlap others and move them to a separate column in the worksheet. Then create the first postmap with the label position set at your choice. Create a second postmap with the label position set to a different location than the first postmap. Then overlay the two maps using the Map|Overlay Maps command. You may have to adjust the label position, possibly using the User Defined function for label position, before you are satisfied with the results.

28Q. How do I change the map coordinates in a DXF file within Surfer?
A. You can use the page coordinates of two calibration points with known map coordinates on your map to create a new DXF with the changed coordinates.  Use the File | Import menu to load the DXF file and display it without axes.  Zoom In on the first known point and write down the XY page coordinates from the status bar at the bottom of the Plot window.  Zoom Out, scroll to the next point and write down the page coordinates.  Choose the File | Export menu, and specify a new file name with the .DXF extension to display the AutoCAD DXF Export dialog box.  Type in the page coordinates under the "Page Rectangle" area and the corresponding map coordinates under the "DXF Rectangle" area.  Although the labels say Lower Left and Upper Right, these two points can be anywhere on the map.  Set the Scaling Source to Application, Format to ASCII, and uncheck all the check boxes in the lower left corner.  Click OK to create the new DXF file.  To load the file into Surfer with map coordinates, use the Map | Load Base Map.

Q29. Is there a way to calculate the Z value in the grid [.GRD] file at particular XY locations?
A. You can use the Grid | Residuals command to calculate the Z value. Create a data file with the XY locations, and a column of 0's that will be used for the zData values. Grid | Residuals subtracts zData - zGrid, so using a column of 0's in the data file will return the negative of the Z value in the grid.

Q30. How are the residuals calculated when the desired location does not fall on a grid node?
A. Surfer uses bilinear interpolation between grid nodes.

Q31. How can I run Surfer minimized in a script?
A. Use the shell( ) command with the minimize option prior to running the CreateObject( ) command:

shell("c:\surfer6\surfer32.exe",2)
set Surf = CreateObject("Surfer.App")

Q32. How can I load Surfer with a different SET file in a script?
A. Use the shell( ) command to specify the SET file on the command line prior to the CreateObject( ) command:

shell("c:\surfer6\surfer32.exe /set=c:\surfer6\tom.set",1)
set Surf = CreateObject("Surfer.App")

Q33. How can I load a new SET file in a script once Surfer is running?
A. Exit Surfer then repeat the shell( ) and CreateObject( ) commands above.

Q34. Surfer does not calculate the minimum and maximum X (or Y) in the grid file correctly when I grid my data. How can I change this?
A. Surfer calculates the minimum and maximum X and Y values for the grid file by getting the minimum and maximum X and Y values from the data file, then calculating the grid line spacing for fifty grid lines in the longer direction ((max - min) / 49), and applying that same grid line spacing in the shorter direction to create square grid cells. If the shorter direction is less than this spacing, the grid minimum and maximum values are adjusted so that (max - min) = grid spacing.  You can change the limits by typing in the actual values from the data file manually.  Click the Data Info button to display these values from your data set.

Q35. What gridding method should I use to grid my data file?
A. The default gridding method, kriging, was selected as a good method for the majority of data sets.

Q36. What's the best method for gridding a data set consisting of digitized contours?
A. No one method is the "best", but you can improve the results of gridding a digitized contour data set by making sure that there is a good supply of data points throughout the map area. If there is a "C"-shaped contour without other contours inside the "C", then the entire C will be gridded as a flat area. The same thing will happen with a closed contour.  You can use the Map | Digitize menu to digitize additional points within the "C"-shaped contours and closed contours and add them to your data file.

Q37. What are the meanings of the parameters in a LVL file?
A. The parameters are defined as follows:

Level = Z or contour value.
Flags = 0 1 2 3 for none, labeled, hachured, both.
LColor = Line color by name "Red" or RGB "R255 G0 B0".
LStyle = Line style, e.g. "Solid", "Invisible".
LWidth = Line width in inches x 1000 so 0.01" = 10.
FFGColor = Fill Foreground Color by name or RGB.
FBGColor = Fill Background Color by name or RGB.
FPattern = Fill Pattern by name, e.g."12.5% Black" "Vertical".
FMode = 1 transparent, 2 opaque.

Q38. How do I use the USGS 7.5 minute DEM data in the SDTS format?
A. Use the following procedure:

1. Go to the USGS GeoData web page at http://edcwww.cr.usgs.gov/doc/edchome/ndcdb/ndcdb.htm l.
2. Scroll down to the section titled 7.5-Minute Digital Elevation Model (DEM) - SDTS format only.
3. If you know the name of the quad, click on FTP via Alphabetical List ( http://edcftp.cr.usgs.gov/pub/data/DEM/7.5min/ ) or FTP via State ( http://edcwww.cr.usgs.gov/doc/edchome/ndcdb/7_min_dem/states.html ).  The Alphabetical List has all the available 7.5 minute quads in separate directories by the first letter in the name of the quad, so BOULDER_CO is in the B directory near BOULDER_WY.  The FTP via State list creates a separate list for each state. Otherwise, click on FTP via Graphics ( http://edcwww.cr.usgs.gov/bin/maptest/coords=55+-130+20+-65 /scale=24/type=dem/zoom=8 ) to get a map of US, and click on the area of interest to zoom in on the 7.5 minute quads.
4. When you click on the quad name, you'll see a file name such as 30.2.1.934551.tar.gz for Boulder. When you click on this file, Save it to disk.
5. The Save As dialog box in Netscape Navigator changes the file name so all but the last period is changed to an underscore: 30_2_1_934551_tar.gz. Press OK to download the file.
6. The next step assumes the use of WinZip ( http://www.winzip.com ) to open this file. In the WinZip Options | Configuration menu, uncheck the option for "TAR File Smart CR/LF Conversion". Double-click on the .GZ file name in Windows Explorer to open the file in WinZip. WinZip will prompt for a file extension for the file 30_2_1_934551_tar. Delete the period at the end of the file name, and change the last underscore to a period to give the file a .TAR extension, e.g. 30_2_1_934551.tar.
7. Answer Yes to the prompt: "Archive contains one file. Should WinZip decompress it to a temporary folder and open it?" This should produce 18 files with the DDF extension and a README.7.5min file.
8. Click on the Extract button, and select All Files. Place the files in a temporary directory.
9. The DDF files are the ones that can be converted with the SDTS utilities that Sol Katz has put on the BLM ftp site. Download the SDTSEDEM.zip file (ftp://ftp.blm.gov/pub/gis/sdts/dem/SDTSEDEM.zip ), unzip it, open a DOS window and run SDTSEDEM.
10. You will be prompted to enter the name of the base and cell SDTS file, which is usually the largest DDF file in the archive, e.g. the Boulder CO quad lists 1116CEL0.DDF as the largest file (365,957 bytes). The first prompt asks for the first four characters of the base SDTS filename (1116), then an output filename (your choice), and then the last two characters of the "cell" filename, usually L0 (the letter "L" and the number zero).
11. If you create a DEM file, this file can be used directly in Surfer in place of a GRD file.

Surfer 7 can load these files without the conversion process.

Q39. Does Surfer work with Windows 98, 2000, and XP?
A. Yes. There have been no problems reported.

Q40. I get the error "Too Many Points" when I try to display a contour map.  I see a gap in the color fill when I try to overlay a filled contour map on a surface map.  How can I resolve this problem?
A. These errors are caused by limits to the number of vertices on a contour, and are dependent on your version of Windows:

Limits to the number of points along a contour
	2D Contour Map	Contour Map on 3D Surface
Windows 3.1	8,000	5,300
Windows 95/98	16,000	10,600
Windows NT	500,000,000	333,000,000

You can get around these limits by creating a smaller grid file, or upgrading to Windows NT.

Surfer 7 has corrected this behavior.

Q41. Using the Surfer Scripter, how do I set the width and height of an exported bitmap (GIF, TIF, BMP, PCX, JPG) with FileExport( )?

Option	Action	Default
Defaults = 1	Set all options to their default values	No
Forget Options = 1	Don't remember optons for later use	No
Width = N	Set N pixels as the output bitmap width	Screen Resolution
Height = H	Set N pixels as the output bitmap height	Screen Resolution
Color Depth = N	Set color depth (WIN32 only).	Color depth on the video display
	...Valid values:
	......1:    Monochrome
	......4:    16 Colors
	......8:    256 Colors
	......24:   True Colors
Automatic=1	Automatic compression (for JPEG)	Yes
Quality=N	Set compression quality 0-100 (for JPEG)	100 (highest quality)

Q42. How can I create my own symbols for use in Surfer, Grapher, and MapViewer?
A. These programs can use any TrueType font for symbols, so you can use a TrueType font editor to create your own symbols including: 

• Softy (shareware)
• Type Tool from Pyrus (commercial)

Surfer, Grapher, and MapViewer also use the symbol sets and Altersym editor from the DOS versions of Surfer and Grapher at the Golden Software FTP site.

Q43. I have invested in Adobe typefaces.   How do I use these type faces with Golden Software products?
A. Since Golden Software's applications are 32-bit, we only support TrueType scalable typeface technology.  If you have a significant investment in Adobe Type 1 faces (i.e., you are using ATM under Windows), we recommend converting them to TrueType format so they may be used with Golden Software products.  Not only will you be able to use them with our software, you'll be able to use them with any Windows program.   We recommend the TypeTool program for this purpose.  It is $99 and can be found at pyrus. 

Q44. How can I calculate the area between contours?
A.  Use the Grid | Volume menu to generate a volume and area report using the GRD file as the "Upper Surface" and the Z level of the first contour as the constant "Lower Surface".  Record the "Positive Planar Area" value from the report.  Next, generate a second report with the same GRD file as the Upper Surface and the Z level of the second contour as the Lower Surface.  Record the Positive Planar Area value from the second report, and subtract from the first value to get the area between the two contours.  You can use the contarea.bas script to automate the procedure.

Q45. When I grid my data file using kriging, it produces a grid file with negative Z values, or with values that go beyond the Z limits in my data file.  How do I change this?
A.  The kriging gridding method was designed to analyze data trends and extrapolate in areas of no data.  There are several methods to eliminate this effect.  Here are three suggestions:

1. Use the Grid | Math menu to eliminate negative values.  First select your existing grid file (A), specify a new name for the output grid file (C), and the formula C = max(A,0).  This formula will convert all negative Z values to 0 in the new grid file.  You can use this method for any value including 0.
2. Choose a different gridding algorithm that does not extrapolate beyond the Z limits in the data file.  Inverse Distance and Triangulation are two such methods.
3. If your data range over several orders of magnitude, it may be beneficial to transform your Z values in the worksheet to logarithmic values.  Open the data file in the worksheet and choose the Compute | Transform menu.   If your data are in column C, and column D is blank, you can use the formula D = log10(C) to calculate the log base 10 of the Z values.  Save the worksheet, and create a grid using column D as the source of Z values.  This method may create negative log10 values, but these values represent small positive Z values.  e.g. log10(Z) = -2, then Z = 0.01.

Q46. How can I make the symbols in the classed post legend the same size as on the map?
A. Surfer was not designed to do this automatically, but you can change the symbol sizes manually.  Create a classed post map with a legend.  Select the legend and copy the legend to the clipboard, clear the warning that Surfer "Can't save linked object by itself", and select the Edit | Paste Special | Picture | Break Apart Metafiles | Paste commands.  Click on the page to paste the object, choose Arrange | Break Apart, select a symbol (now converted to a polyline or polygon) and drag the corner of the symbol to the desired size, which is displayed in the Status Bar at the bottom of the Surfer window.

Q47. How can I enter a "null value" (a value that is ignored when gridding or performing mathematical calculations) into the Surfer worksheet?
A. Surfer ignores any text strings (non-numeric values) when gridding and when performing Data | Transform in the worksheet.  Any of the following can be used:

            "-9999", N/A, "no data", x99

In a text editor, program, or script, add quotes around a number to designate it as a text string.  In the worksheet, insert a single quote (apostrophe) at the beginning of the number to convert it to text.  Quotes around a text string with spaces insure that the entire string is read as a single item.  A mix of numbers and text without spaces is read as a text string.

Q48. How do I display the scale bar in miles or kilometers when the XY coordinates are in degrees of latitude and longitude?

A. First convert the map X Scale and Y Scale to Cartesian coordinates (i.e. miles, feet, kilometers, meters), because one degree of latitude does not cover the same number of miles as one degree of longitude. For an approximate conversion from latitude and longitude degrees to miles or kilometers, use the following formulas for a spherical projection:   1 degree latitude  = 110.6 km                      = 68.703 mi   1 degree longitude = 111.3km * cos(latitude)                      = 69.172mi * cos(latitude) To set the scale bar of a map, use the formulas to convert latitude and longitude to the desired coordinates. For the map of Nevada USA included with Surfer (nv.gsb) the center of the map is approximately (-117, 39). Using the formulas:   1 degree latitude  = 68.703 miles   1 degree longitude = 69.172 * cos(39)                       = 53.757 miles To set the X and Y to the same scale in miles, select the map and choose the Map | Scale menu. Disable the Proportional XY Scaling checkbox in the lower left corner of the Scale dialog box. If the X scale is set to 1.0 in = 1 Map units (degrees longitude), calculate the ratio of X to Y as 53.757mi / 68.703mi = 0.78245. Specify the Y scale as 1.0 in = 0.78245 Map Units. The default scale bar is created in degrees with a Cycle Spacing = 1 and Label Increment = 1. To change the scale bar to 50 mile increments, change the Cycle Spacing to 50mi / 53.757mi per degree or 0.93 (degrees) and the Label Increment to 50 (miles).

Q49. When I change the map limits on a post map, data point labels disappear for points that are on the edges of the map but inside the limits.  How can I display these labels?
A. Increase the map limits to include the area where the labels plot.

Q50. I am having a problem printing ("Out of global memory" error, only a portion of the map prints, etc.).
A. You may be able to work around the problem by changing some of the printer settings. Different printer drivers have different settings, but here is a list of the most common remedies:

• Turn off print spooling.
• Change the print mode to "raster" or "bitmap" to reduce the printer memory requirements.
• Change the printer driver to use the computer's memory instead of the printer's memory.
• PostScript drivers often require more memory than non-PostScript drivers for the same printer. Change drivers if possible and test the print results.
• Check for other compatible printer drivers in your printer documentation. For example, the HP LaserJet 4 driver could be used with the LaserJet 5 printer.
• Enable the Page Protect mode if available.
• Verify the version of your printer driver and possibly update it. For example, the HP DesignJet 750C driver version 4.33 requires 80% less memory than version 4.11
• Turn off View | Auto Redraw to free up additional memory.
• Resample the bitmaps in a graphics program (Corel Draw, Paint Shop Pro, PhotoShop) to reduce the number of pixels and color depth in the bitmaps.

If the remedies above do not help, please contact technical support with the exact nature of the problem, your operating system (i.e. Windows 98), the printer model, and the print driver version number.