Presets
Presets in LeanHRPT refer to mathematical expressions evaluated with muparser that are used to calculate RGB values from raw channels. This allows the user to create images that are far more complex than what basic RGB compositing allows without having put the data through another program like GIMP or Photoshop.
This page will focus on describing the default presets included with LeanHRPT. To learn about the expression syntax and how to make your own; see the Custom presets page.
Also known as rgb221, the NIR preset maps a visible red and a near-infrared band into an RGB composite. As it is applicable to all four HRPT satellite types, it is often considered to be the default false color composite for HRPT.
Also known as rgb321, the SWIR preset usess shortwave-infrared, near-infrared and visible bands to create an RGB composite. Provides more pleasing land color. Although a side effect of SWIR is that clouds gain a toothpaste tint.
(FengYun-3 only)
Maps three visible light bands of the imager directly onto the according RGB channels of the image.
Combines the NIR and SWIR composites to keep SWIR's nicer land colors while eliminating the toothpaste cloud tint.
(FengYun-3 only)
Combines NIR together with visible light bands to create a more pleasing image. Provides better land contrast than RGB.
(FengYun-3 only)
Combines SWIR together with visible light bands to create a more pleasing image. Provides better land contrast than RGB.
Calculates the vegetation index. The resulting image indicates higher vegetation areas as brighter (-1.0 = black, 1.0 = white).
Combines the NDVI with NIR false color to provide an color image. The normally green vegetated areas of NIR are exaggerated based on how vegetated the land is (Note: this is mainly for informative and aesthetic purposes and not very useful for actual NDVI measurements).