8 Application Programmer Interface to Viewers

The low-level analysis widgets used in Event Browser are very general and may be called from the IDL prompt or from your own IDL programs.

If you need to graph a sampled 1-D function stored in the vectors ``x'' & ``y'', try using the function_1d tool

• function_1d, id, x, y

instead of the PLOT command. The parameter ``id'' should be an undefined variable.

If you need to visualize a sampled 2-D function (an image) stored in the 2-D array ``image'', try using the function_2d tool

• function_2d, id, image

instead of the TVSCL, SHADE_SURF, SURFACE, or CONTOUR commands. If your image is stored in a FITS file (instead of in an IDL variable), try using the fits_viewer tool (no parameters) instead of applications like saoimage.

If you need to study the distribution of a univariate dataset stored in the vector ``x'', e.g. you want to make a spectrum from a set of energy measurements, try using the dataset_1d tool

• dataset_1d, id, x

instead of the HISTOGRAM and PLOT commands.

If you need to study the distribution of a bivariate dataset stored in the vectors ``x'' & ``y'', e.g. you want to make an image from a list of photons, try using the dataset_2d tool

• dataset_2d, id, x, y

instead of the HIST_2D, TVSCL, SHADE_SURF, SURFACE, or CONTOUR commands.

If you want to form a color image from two (Hue/Brightness color model) or three (RGB color model) co-aligned arrays, try using the true_color_image tool

• true_color_image, id, hue_image, value_image
• true_color_image, id, red_image, green_image, blue_image, /RGB

These widgets accept a wide variety of keyword parameters - see the comments in the appropriate .pro files. All of these tools will work with multiple datasets specified by the keyword DATASET_NAME, e.g.

• dataset_1d, id, x1, DATASET_NAME='One'
• dataset_1d, id, x2, DATASET_NAME='Two'

Note that these viewer widgets adhere to a PSU-defined protocol regarding the assignment and use of colors in the IDL color table. Execution of these viewer widgets leaves the color table in an altered state - the standard IDL routine TVSCL should not be used without re-loading the color table with the IDL command loadct.