In Surfer 14 and newer versions, you can follow the instructions here to edit your grid in the grid editor window, thereby changing the contour lines: Edit a grid file in Surfer. Alternatively, you can follow the instructions below to export the contours to a vector file, plot the vector file as a base map, reshape the contour lines, and then convert back to a contour map:
- Select the contours and click Map Tools | Layer Tools | Export Contours.
- Choose to save it in an AutoCAD DXF file, give the file a name, and click Save.
- Click Home | Add to Map | Layer | Base, select the DXF file and click Open.
- Click OK in the DXF Import Options dialog. The base layer of the contours is added to the original map.
- Click the + icon next to the Base(vector) layer to expand the layer and view all polylines/polygons within the layer. Each has a ZLEVEL attribute equal to the Z value of that contour line. You can see the attributes by selecting an object and clicking the Info tab in the Properties window.
- Uncheck the check box next to the Contours layer in the Contents window so you no longer see the contour map.
- Select the polyline/polygon in the Base layer to be reshaped and click Features | Edit Feature | Reshape to display the vertices of the object.
- Reshape the selected contour.
- Repeat steps 8 and 9 for any other contours to be reshaped. When you're done reshaping, press ESC on your keyboard to exit Reshape mode.
- To add additional contour lines, click Features | Insert | Polyline or Polygon, then draw the contour on the map, double clicking the last point to finalize the object.
- Press ESC when you're done drawing new contours to exit drawing mode.
- Right click on the Base(vector) layer in the Contents window and click Open Attribute Table.
- Move the Attribute Table off to the side of your map.
- Click in one of the empty ZLEVEL cells. The associated shape will be selected on the map. Enter the appropriate contour level value for that ZLEVEL into the Attribute Table.
- Repeat for all contours you added, closing the Attribute Table when you're done.
- Click Grids | New Grid | Grid from Contours.
- In the Grid Contours dialog, select your base layer from the Contour Source list.
- In the Select Field dialog, choose ZLEVEL from the list, then click OK.
- In the Output Grid section, give your grid file a name.
- Change the New layer type to Contour.
- Set any other desired options, then click OK. A new map is created with a contour layer based on the grid from your vector file.
Please contact us if you would like to add your vote to our suggestion file for a way to reshape contour level lines.
Updated December 19, 2021