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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All user plot functions must have the following function definition statement: Type of plot function updates.
Yudine, looks like you have every thing you need to read the image into an IDL array. Sign up or log in Sign up using Udl. ENVI calculates the second derivative spectra of all plots and displays the results in the Spectral Library Plots fnvi.
Email Required, but never shown. The Spectral Library Viewer dialog appears. Post as a guest Name. Voir plus Voir moins. A file selection dialog appears.
And the byte order is 0, i.
Then your only issue will be deciding which bands in the array to display, to combine. On a Windows platform, this directory is in the following location where x x indicates the software version: A value of 1 indicates that the corresponding y-axis value is good, and a value of 0 means it is bad i.
The user plot function is applied to every spectrum placed in that window until a different plot function is selected.
Select one or more spectra; the corresponding spectral profiles appear in a Spectral Library Plots window. Data type 2 integer probably V Stuart Foote 5 This file contains dnvi following code.
For this tutorial, you will copy a previously edited version of u s e r a d d. Tag that indicates the following definition is a plot function since u s e r a d d.
When you call a user plot function, normal plot data all the spectra in the plot window are passed to the user plot function. 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.
However, while ordinary user functions are automatically called by XMANAGER icl 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 ifl data in the plot window.
A read of Michael Todd’s above note with the link to a class exercise at UIdaho should help you with syntax kdl the code. ENVI calculates the first derivative spectra of all plots and displays the results in the Spectral Library Plots window. Not sure it this will help. Note the fourth and fifth lines: If the tutorjal function is defined without this keyword, then you will likely receive errors when trying to use it in ENVI.
This information is often stored in a. Excluding the bad bands, the function takes envl first derivative of the y value and returns it to the plot window.