ENVI IDL TUTORIAL PDF
Introduce the student to the initial concepts and use of IDL and ENVI to: • import, analyze, and output image data. • learn to interface between ENVI input/outputs. This tutorial is designed to introduce you to the basic concepts of the ENVI software and some of its For ENVI +IDL, type envi at the UNIX command prompt. These programs (scripts) are based on the IDL programming language and are run in the IDL environment, either by loading the ENVI+IDL program or simply.
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ENVI calculates the first derivative spectra of all plots and displays the results in the Spectral Library Plots window.
Note that 1st Derivative will be placed immediately after the Binary Encoding menu option. Sign up or log in Sign up using Google. This file contains the following code.
A file selection dialog appears. This applies only to Z Profile windows and will be undefined for all other plot windows. IDL seems to support reading tif files. Home Questions Tags Users Unanswered. Sign up using Facebook. However, while ordinary user functions are automatically called by XMANAGER and receive the event structure variable as a positional parameter, plot functions are automatically called by ENVI and receive several variables as both parameters and keywords that are related to the data in the plot window.
Documents Ressources professionnelles Informatique. Data type 2 integer probably A Spectral Library Input File dialog appears. Voir plus Voir moins. ENVI calculates the second derivative spectra of all plots and displays the results in the Spectral Library Plots window.
Not sure it this will help. Yudine 27 1 3.
Geological Remote Sensing Group
This information is often stored in a. Of course for any geospatial work outside IDL you would need to know the nominal pixel size and coordinates of at least 3 control points for image registration. Keyword variable that must be present to receive extra variables that ENVI may need to pass into the plot function. If the plot function is defined without this keyword, then you will likely receive errors when trying to use it in ENVI.
Yudine, looks like you have every thing you need to read the image into an IDL array. The plot function is applied to the data, and the resulting data are returned to the plot window where they are displayed. Type of plot function updates. Note the fourth and fifth lines: The Spectral Library Viewer dialog appears.
This function accepts x and y data and a list of bad bands. The following code appears in the IDL Editor: A value of 1 indicates that the corresponding y-axis value is good, and a value of 0 means it is bad i.
When you understand how these functions work, close the files. On a Windows platform, this directory is in the following location where x x indicates the software version: A read of Michael Todd’s above note with the link to a class exercise at UIdaho should help you with syntax of the code.
Using the fourth field above as an example, the ttorial is as follows: Vector of ones and zeros with as many elements as x-axis data points. The user plot function is applied to every spectrum placed in that window until a different plot function is selected.
Vector whose values identify the band positions of the bad bands in the Z Profile data.