Surfer 12: Export Map and Non-Map Objects with Georeferencing

Transcription

1 Surfer 12: Export Map and Non-Map Objects with Georeferencing Surfer keeps track of objects using two separate systems: map coordinates and page coordinates. All map objects, i.e. objects within the map frame, are stored in map coordinates. Everything outside of the map frame (non-map objects like color scales and drawn objects) are stored in page coordinates. In Surfer 11 and earlier, if you had a combination of map and non-map objects that you wanted to export to map coordinates so your KML or DXF file would be properly georeferenced, you had to perform a double-export workaround, detailed in the Newsletter 48 article Converting Drawn Objects from Page Coordinates to Map Coordinates. Surfer 12 has added the option though to export map and non-map objects in map coordinates on the very first export in only a few steps. To illustrate this, let s compare the process in both Surfer 11 and Surfer 12. Open Surfer Open Wateshed.srf from the Samples directory. By clicking on the Map in the Object Manager and then the Limits tab in the Property Manager, we can see that the limits of the map are to in the x direction and 39 to 41 in the y direction. These are latitude and longitude coordinates for an area in Colorado, United States. The coordinate extents of the map can be seen in the Limits tab of the Property Manager. 2. Collapse the Map object in the Object Manager by clicking on the minus sign next to it. You ll notice that there s still a Text object visible. This is a non-map object. The Text object is outside of the Map object so it is a non-map object. The Map frame and everything inside are map objects.

2 The map objects are listed under the Map object in the Property Manager. 3. Click File Export. Choose type KML, give your file a name, and click Save. In the Export dialog, set the Save as type to KML Google Earth KML (*.kml), give your file a name, and click Save. 4. In the Export Options dialog you ll notice that the File Rectangle units match the Page Rectangle units, and they don t match the extents of the map. This is because they re in page units, inches in this case. They re in page units because Surfer doesn t know how to reference the non-map object in map units, so it puts everything into page units.

3 Because the non-map object is in page coordinates, the entire map will export in page coordinates. That is why the File Rectangle and Page Rectangle units match in the Export Options dialog. If you click OK in this dialog, you map will export in the units shown under the File Rectangle (page units). Other programs, like Google Earth, will interpret these as latitude/longitude coordinates, placing the map in Africa instead of Colorado.

4 The map shows up in Africa in Google Earth because the page coordinate units are taken as lat/lon values. Now let s try the same thing in Surfer 12. Open Surfer Open Wateshed.srf from the Samples directory. 2. Click File Export. Choose type KML, give your file a name, and click Save. 3. In the Export Options dialog you ll notice that Scaling source is no longer a radial button with Application or Saved options, it is now a dropdown menu where you can select Paper space (page units), Saved settings, or Map: 3D Surface-CO_RockyMtn.grd. If we had multiple maps in our project, each map would have an option in this dropdown menu.

5 The scaling source has changed from a toggle to a dropdown menu, with options for Paper space (page units), each of the Maps in the project, and Saved settings. Saved settings is the same as the Saved option before. It allows you to use the scaling options that have been saved in a previous export with the Save scaling info checkbox. The Paper space (page units) option will export in page units (i.e. inches and centimeters). Thus, the File Rectangle units will match the Source Rectangle units.

6 When the Scaling source is set to Paper space (page units), the File Rectangle units match the Source Rectangle units. Each of the Map options will export in the coordinate system of that map. In this case, the map is in lat/lon so the File Rectangle units are appropriate lat/lon values for Colorado.

7 When the Scaling source is set to one of the Map options, the File Rectangle units match the extents of that particular map in the project. 4. Choose the Map: 3D Surface-CO_RockyMtn.grd option, verify that the File Rectangle units look appropriate, and click OK. Now when we open this map in Google Earth, it will show up in Colorado rather than in Africa, and it was all accomplished with one export rather than two. With this one Surfer 12 export, the map and the non-map text appear at the correct location in Google Earth, in Colorado rather than in Africa.