Resumen
Enhances an image by changing properties such as brightness, contrast, and gamma through multiple stretch types based on statistics.
Debate
For more information about how this function works, see the Stretch raster function.
The referenced raster dataset for the raster object is temporary. To make it permanent, you can call the raster object's save method.
Sintaxis
Stretch (raster, stretch_type, min, max, num_stddev, statistics, dra, {min_percent}, max_percent, {gamma}, {compute_gamma}, sigmoid_strength_level)
Parámetro | Explicación | Tipo de datos |
raster | The input raster. | Raster |
stretch_type [stretch_type,...] | Specify the type of stretch to apply to the image.
(El valor predeterminado es 0) | String |
min | Set the lowest pixel value for the output histogram. The output minimum (min) and output maximum (max) will set the range of values that will then be stretched. (El valor predeterminado es None) | Double |
max | Set the highest pixel value for the output histogram. The output maximum (max) and output minimum (min) will set the range of values that will then be stretched. (El valor predeterminado es None) | Double |
num_stddev | Specify the n value for the number of standard deviations to use. This method is used to emphasize how much feature values vary from the mean value; it is best when used on normally distributed data. (El valor predeterminado es None) | Double |
statistics [statistics,...] | By default, the statistics used are retrieved from the data; however, any statistic values you enter in this parameter will be used instead. Statistics are specified as: [[<min>, <max>, <mean>, <standardDeviation>] [<min>, <max>, <mean>, <standardDeviation>] [<min>, <max>, <mean>, <standardDeviation>]] (El valor predeterminado es None) | Double |
dra | Calculate statistics from only the pixels displayed on your screen. The statistics parameter is ignored when DRA is True.
(El valor predeterminado es None) | Boolean |
min_percent | Specify the percentage of the low values to exclude when the PercentClip stretch is specified. Valid values range from 0 through 99. (El valor predeterminado es None) | Double |
max_percent | Specify the percentage of the high values to exclude when the PercentClip stretch is specified. Valid values range from 0 through 99. (El valor predeterminado es None) | Double |
gamma | Specify gamma values for each band to apply to the image. For example, a three-band image would have three values, such as [<gamma1>, <gamma2>, <gamma3>]. (El valor predeterminado es None) | Double |
compute_gamma | Calculates the best gamma value to render the exported image based on an empirical model.
(El valor predeterminado es None) | Boolean |
sigmoid_strength_level | Determines how much of the sigmoidal function will be used in the stretch. A low value such as 1 will only use the middle portion of the curve, which tends to produce dull and faint colors. A high value such as 6 will use the entire curve, which tends to produce bold and sharp colors. The valid range is 1 through 6. (El valor predeterminado es None) | Integer |
Tipo de datos | Explicación |
Raster | The output stretched raster. |
Muestra de código
Enhances an image by changing properties such as brightness, contrast, and gamma through multiple stretch types based on statistics.
import arcpy
Stretch_raster = arcpy.sa.Stretch(imagePath1, "PercentClip", None, None, None, None, True, 0.25, 0.75, None, None, None)