You might want to open the new BLN file in the Surfer worksheet and double check that the BLN flag value (0 or 1) is correct. Copyright © 2016 Golden Software, LLC. All rights reserved. The names and logos for Surfer, Grapher, Voxler, MapViewer, Didger, Strater and Golden Software are registered trademarks of Golden Software, LLC. In Surfer you can load a BLN file as a base map, reshape the polygon and then resave it as a BLN file. The exact steps are: You might want to open the new BLN file in the Surfer worksheet and double check that the BLN flag value (0 or 1) is correct. Today is an exciting day with the release of our newest product, Raster Tools! Raster Tools is a powerful add-in to Esri’s ArcGIS for Desktop (ArcMap) software which creates accurate raster datasets. With Raster Tools, users have access to twelve adv... Source.