# <>Scientific Software in IDL

This page offers IDL routines addressing a variety of topics.  If you have problems or wish to share a program contact Mark Hervig (m.e.hervig@gats-inc.com).

## Thermodynamics

• Density of liquid H2SO4-H2O,  HNO3-H2O,  or ternary HNO3-H2O-H2SO4 solutions (lta_density.pro)
• Equilibrium composition of sulfate aerosols (wt.% H2SO4),  according to Steele and Hamill, 1981 (sulfate.pro)
• Equilibrium composition of sulfate aerosols (wt.% H2SO4),  according to Tabazadeh et al., 1997 (sulfate_tabaz.pro)
• Altitude change between two pressure levels using the hydrostatic equation (hydrostatic.pro)
• Column ozone amount in Dobson units (dobson.pro)
• Ice density for 93K < T < 273K (ice_density.pro)

## Geometry

• Great circle distance and heading between two locations (great_circle.pro)
• Relate angular field of view at the spacecraft to linear distance subtended at tangent for a limb view (ang2lin_fov.pro)
• Relate linear distance subtended at tangent for a limb view, to angular field of view at the spacecraft (lin2ang_fov.pro)
• Calculate path length of the tangent point sample volume for a limb view from space (tan_path_len.pro)
• Make a set of X & Y points that will form a circle (circle_draw.pro)

## Miscellaneous

• Two-point linear interpolation (interp_2pt.pro)
• Compute a histogram for your data,  the median value (most frequent),  and the mean and std. deviation (histo.pro)
• Find all interpolates on a multi-valued function (interp_all.pro)
• Generate a set of random numbers that has a mean value below a specified limit (get_random_nums.pro)
• Find the half power points for a curve (e.g., a FOV or RSR curve) (half_power.pro)
• Generate a uniform logarithmic series of numbers (range_logx.pro)
• Generate a uniform series of numbers (range_x.pro)
• Analog to digital converter (a2d.pro)