Information for creating a uniform grid from spares data or irregular set of points using routines in PV-Wave and How to create postscript files of images displayed in windows 01/13/99 There are two directories in the "grid" directory: new and old. The old directory work best with the gridding algorithm used in PV-Wave prior to 1993, and the new directory uses gridding algorithms that work best with either sparse or dense grids. To get more in depth explanation use the PV-WAVE help by typing in help at the PV-WAVE command prompt: wave> help . In both the new and old directory there are two directories: abc and xyz. The abc directory creates a simple plot where all 10 points fall within a plane and the xyz directory also contain the same 10 points but forms an irregular surface that resulted from a slight perturbation out of the same plane in the abc example and forms an irregular surface with some nuerical artifacts. In both examples postscript files are generated for "tv" (black-white) image plot, "shaded- surface" plot, and the "contour" plot. The generation of a postscript file is show below where the image is saved in filename example.ps. ;--- create postscript file from the image that was displayed ---- ; in the window with (200,200) pixels ; s1=tvrd(0,0,200,200) set_plot,'ps' device,/inches,filename='example.ps'$ ,/landscape,scale_factor=0.8,bits_per_pixel=8 tvscl,s1 device,/close set_plot,'x' ;----------------------------------------------------------------- Most graphic software packages do not grid sparse or irregular data simply because interpolation of data can lead to serious distortions. It is usually assumed that if regular-uniform data is required by a particular software program the user must create this uniform mesh of data. Of course there are software packages such as PV-Wave that will grid your data for you. None-the-less be careful not to always believe these interpolations.