Hello Forum, Hoping that somebody out there can help me out. I need to export raster surfaces from IDL into ESRI GRID format. I've been writing them out to FLT/HDR files and importing them in Arc, but the time has come to write directly to GRID. With ArcView 3x, ESRI provides a C API for GRID I/O (gioapi.h), and the avgridio.dll and avgridio.lib files are also available I have the Borland C compiler v5.5, though I'm not a C programmer by any stretch of the imagination . I presume the preferred method is to use a DLM. I've gone through all the documentation including Ronn Kling's book but can't quite put the pieces together. Has anybody already worked this out? Any assistance would be greatly appreciated. Kalr