To add attributes to contours and then create a grid file:

1. Click Home | New Map | Base.
2. In the Import dialog, select the vector file containing your contour polylines and click Open.
3. Right click on the Base layer in the Contents window and click Open Attribute Table.
4. In the Attribute Table dialog, click the Add Field button (​) to add an attribute.
5. Enter and Attribute name of ZLEVEL and click OK.
6. Select a polyline on the map. The associated polyline is highlighted in the Attribute Table dialog. 
7. Type in the contour level in the ZLEVEL column in the Attribute Table.
8. Repeat steps 5-6 for the other polylines.
9. Click Grids | New Grid | Grid from Contours.
10. In the Grid Contours dialog, select your base layer from the Contour Source list.
11. In the Select Field dialog, choose ZLEVEL from the list, then click OK.
12. In the Output Grid section, give your grid file a name.
13. Change the New layer type to Contours if you wish to create a new contour map from the new grid file.
14. Set any other desired options, then click OK.

A contour map is created from the new grid file, which you can now visually compare to the original contours in the base layer.

Updated December 8, 2021