NASA helps plot raster images of geo-gridded data, with Panoply
Panoply is a free and portable program created by NASA to facilitate plotting raster images. You can use it to browse NetCDF, GEMPACK, HDF, GRIB and more datasets, having also the option of editing geo-gridded arrays.
The program requires the Java environment. It futures tabbed interface letting you browse datasets, bookmars and catalogs easily. You can use it to export or print GIF, KMZ, PDF, PNG, AVI, PS, MOV formats.
Plots can be created from variables; you can enjoy 2D, geo-gridded or line plots. The program features plot zoom and color customization. Panoply will also let you add two arrays in a single plot, using differences, sums or averages, select and use particular arrays, use map projections, etc.
Features: Slice and plot geo-referenced latitude-longitude, latitude-vertical, longitude-vertical, time-latitude or time-vertical arrays from larger multidimensional variables * Combine two geo-referenced arrays in one plot by differencing, summing or averaging * Plot lon-lat data on a global or regional map using any of over 100 map projections or make a zonal average line plot * Save plots to disk GIF, JPEG, PNG or TIFF bitmap images or as PDF or PostScript graphics files * Export animations as MP4 video or as a collection of invididual frame images, and more.
Note that you may need some time to become familiar with all the functions and the interface.