Map projection support is a very powerful new feature in Surfer 10. It allows you to combine data (data, grid and base map files) from different coordinate systems, and convert that data to a new coordinate system for the map to display. It saves you time and effort since you don’t have to do this conversion separately in a different program before using the data in Surfer. For example, you could create a contour map from a grid file in State Plane coordinates, add a post map layer using data in lat/long coordinates, and display the map in any coordinate system you wish. When Do I Use Coordinate Systems? You do not always need to set the coordinate system for the map layers or the map. You only need to specify the coordinate systems for the map layers and map if: Assigning and converting the coordinate systems in Surfer 10 is a simple two step process: set the coordinate system for the map layer(s), and set the coordinate system for the map. It is important to distinguish the difference between setting the coordinate system for the map layer versus setting the coordinate system for the map. They are in two different places in the program and have different functions. When using coordinate systems with maps, the first thing you want to do is set the coordinate system for the individual map layers in your map. When you select a map layer in the Object Manager (ie. a Contours layer), the Coordinate System tab in the Property Manager shows the coordinate system for the source data, grid or base map file used to create that map layer. If the source data file has an assigned coordinate system, or a reference file with this information, then in most cases Surfer will read that information and automatically set the coordinate system for that layer. If the source data file does not have an assigned coordinate system, then the coordinate system for the layer is set to Unreferenced local system. Click the Set button to set the source coordinate system for the data used to create the map layer. Once the coordinate system is set for the layer, it should not be changed unless you change the source data or grid file. Maps After the coordinate system is set for the map layers, you have the option of changing the coordinate system displayed by the map. This is the target coordinate system. When you select Map in the Object Manager, the Coordinate System tab in the Property Manager shows the target coordinate system that the map will actually be displayed in. Click the Change button to change or convert the coordinate system of the map to any coordinate system you want. When you change the coordinate system for the map, all map layers will be converted from their source coordinate system to this target coordinate system for display purposes. Step-by-Step Example We can walk through this in a step-by-step example, using the files located in the Surfer Samples folder in the installation directory. Golden Software’s products give you the best value for your money out of any software on the market. Zivko Terzic Geophysicist 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. Source.