Graphics Display Programs

• FSC_ZIMAGE Zooms into image with rubberband selection technique. (Uses direct graphics.)
• FSC_ZPLOT Zooms into line plot with rubberband selection technique.
• MAP_GSHHS_SHORELINE Draws shorelines using the GSHHS data base in manner of MAP_CONTINENTS.
• MPI_PLOT A wrapper for PLOT and OPLOT commands that allows interactive configuration of keywords.
• PRECIPMAP Demonstrates how to fit a map coordinate system to a map-projected image.
• READ_TOMS_AEROSOL Demonstrates how to overlay satellite imagery on a map projection.
• STATIONPLOT Plots meteorological "station" data. Used with WINDBARB
• TERMINATOR_MAP Draws map with day/night terminator displayed.
• WINDBARB Plots meteorological wind barbs.
• WINDOWIMAGE Interactively change the contrast and brightness of an image using direct graphics.

FSC_ZIMAGE

This program allows you to "zoom" into a portion of an image. It illustrates how to use pixmaps and the "device copy" technique to create a rubberband box on top of an image. It also illustrates a very powerful technique of having several event handlers for an individual widget and switching between them. This makes your programs more modular and easier to maintain. (For the equivalent program written with object graphics, see ZOOMBOX.)

	FSC_ZPLOT
	This program shows you how to "zoom" into a line plot. Similar to FSC_ZImage, the program allows you to designate a zoom area with a rubberband box. The program also demonstrates a device independent way to work with drawing colors.

MAP_GSHHS_SHORELINE

Some people prefer the higher precision of the Global Self-consistent, Hierarchical, High-resolution, Shoreline (GSHHS) database for drawing continental outlines and other shorelines to the built-in CIA database that comes with IDL. This program works in way analogous to MAP_CONTINENTS, in that it allows the user to draw shoreline boundaries into a map projection space set up with either MAP_SET or MAP_PROJ_INIT. You see example output below from running the program with the highest resolution GSHHS file. Detailed instructions for using this program are described in an accompanying article.

MPI_PLOT

This program is a wrapper program for the Plot and OPlot commands. Its purpose is to make it easy for the user to modify Plot keywords and parameters through interactive dialogs. Changes are implemented immediately, allowing the user to quickly make a plot ready for publication-quality applications, web output, etc. Users can save the plot in PostScript format, as well as JPEG, TIFF, PNG, BMP, etc. outputs. Users can make changes to program colors, fonts, character sizes, line styles, and plot symbols, among many other parameters. The program window is completely resizable. Using the program is as simple as using the Plot and OPlot commands. IDL> MPI_Plot, data, Color='Saddle Brown', DataColor='Navy', Background='Ivory' IDL> MPI_Plot, moredata, Color='Red', LineStyle=2, /Overplot Below, you can see the MPI_Plot program and the dialog (at reduced size) that gives you access to plot and axis keywords and parameters.

	PRECIPMAP
	This program is strictly a demonstration program to illustrate how to create a map coordinate system on top of an image that is already gridded into a map projection. It uses a precipitation image that is gridded into a polar stereographic map projection.

READ_TOMS_AEROSOL

This program is strictly a demonstration program to illustrate how to overlay satellite data onto an IDL map projection in a device-independent way. That is to say, the output of the program should look identical (as much as is reasonably possible) on the display and in PostScript output. The program is discussed in detail in this tutorial article. Output of the program looks similar to the image below.

	TERMINATOR_MAP
	This program demonstrates how to calculate and draw a day/night terminator on a map projection. It requires programs from both the Coyote Library and the Johns Hopkins University Applied Physics Lab (JHUAPL) IDL Library. Users can specify seven different map projections, as well as the date and time of a particular view.

	WINDBARB
	This program allows you to plot meteorological wind barbs on a map or other graphical display. Wind barbs show the direction and speed of the wind at a particular location. The figure below shows wind barbs plotted along with station plots on a map projection. To plot stations, you will require the StationPlot program, too.

	WINDOWIMAGE
	This program demonstrates how to write a program to interactively change the contrast and brightness of an image. This is sometimes called the window level and window width. This kind of interaction is often required when working with 16-bit medical images. Details of the algorithm used in this program can be found in the article Image Contrast and Brightness Adjustment.

	Web Coyote's Guide to IDL Programming