[Go to Previous] [Go to Next]


Description of Formulas - Imagery

The following describes each formula included in the Imagery Formulas section of McIDAS-V.

Geolocate an Image (Upper Left Lat, Upper Left Lon, Lower Right Lat, Lower Right Lon - Takes an image data object and a lat/lon bounding box and adds a lat/lon domain to the data. This formula is commonly used in conjunction with another formula.

Input Parameter Definition

Upper Left Lat

Upper left latitude value (default=90).

Upper Left Lon

Upper left longitude value (default=-180).

Lower Right Lat

Lower right latitude value (default=-90).

Lower Right Lon

Lower right longitude value (default=180).

Image over topography - Obtains the latitude coordinate from the grid and returns a grid of the latitudes at each point.

Mask Function - Allows you to specify a threshold value where only data greater than, less than, greater than or equal to, less than or equal to, or equal to values will display.

Input Parameter Definition

comparison

The mathematical operator applied to the cutoff value to determine which data values are displayed.

cutoff

The numerical boundary that will be applied to the comparison value.

useNaN

Default value = 1

Mask Within Range - Allows you to specify a numerical range where data values will display.

Input Parameter Definition

minValue

The minimum data value that will be displayed.

maxValue

The maximum data value that will be displayed.

useNan

Default value = 0

Scale images to brightness ranges - Displays your selected parameter in the Main Display window. Instead of using the color bar range that would be customary for your selected parameter, the standard range for brightness values will be used (i.e. 0-255).

Three Color (RGB) Image - Combines three images as a RGB image when the 3 Color (RGB) Image display type is selected. When you select Create Display, a Field Selector window will open. The fields in this window are red, green, and blue. Once you click OK, an RGB image will be created in the Main Display window. Below is the Layer Controls tab for the 3 Color (RGB) Image display type.

Image 1: Three Color (RGB) Image
Image 1: Three Color (RGB) Image

Three Color (RGB) Image (Auto-scale) - Combines three images as a RGB image when the RGB Composite display type is selected. When you select Create Display, a Field Selector window will open. The fields in this window are red, green, and blue. Once you click OK, an RGB image will be created in the Main Display window. After the display is created, you have the ability to change the ranges for the red, green, and blue values, as well as the gamma values. Below is the Layer Controls tab for the RGB Composite display type.

Image 2: RGB Composite
Image 2: RGB Composite

[Go to Previous] [Go to Next]