ENVI Pocket Guide®

Volume 2 Intermediate

GEOSPATIAL

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Authored as a Derivative from ENVI Bootcamp & ENVI Documentation Center By:CW3 Augustus Wright, 125D EN
In association with the U.S. Army TWI Program.
©2020 Harris Geospatial Solutions, Inc. All rights reserved. ENVI, IDL and L3Harris areregistered trademarks of L3Harris Technologies, Inc. All other marks are the propertyof their respective owners.
2CONTENTS¢ Getting Started……………….………..……....5¢ Section 1: Grid Reference……………………. 6 - 11
¢ Section 2: Band Math………………….……....12 - 15
¢ Section 3: Layer Stacking………………….....16 - 20
¢ Section 4: SWIR Bands………........................21 - 28
¢ Section 5: Spectral Analysis……………...…..29 - 38
¢ Section 6: Image Calibration………..…...…..39 - 42
¢ Section 7: LiDAR Feature Extraction............ 43 - 52
¢ Section 8: Batch Processing.......................... 53 - 66
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The ENVI® Pocket Guide is a quick reference booklet not intended to beread from cover to cover although it can be. The intent is to provide users
with succinct steps on how to accomplish common tasks in ENVI.
If you need or desire comprehensive explanations of tasks from this guiderefer to the following resources:

4ENVI Documentation Center

ENVI Help Articles

nv5geospatialsoftware.com/docs

nv5geospatialsoftware.com/Support

ENVI Tutorials

Tech Support

nv5geospatialsoftware.com/docs/tutorials.html(+1)303-413-3920

ENVI Videos

Email Support

nv5geospatialsoftware.com/Learn/Videos

geospatialinfo@nv5.com

GETTING STARTEDOPENING ENVI
1. Please reference ENVI Pocket Guide Volume 1 | BASIC if you need
instructions on how to open ENVI, load and remove data, descriptionsof the interface components, and basic data preparation procedures.

ENVI Pocket Guide Volume 1 | BASIC
provides an introduction to familiarize users with common methods
for opening ENVI, loading data, navigating, and performing stretches.
You are currently referencing
ENVI Pocket Guide Volume 2 | INTERMEDIATE
which expounds a step further on intermediate procedures using ENVI,
IDL and ENVI LiDAR, assuming you have already mastered the basics.
5GRID REFERENCE
1. Load an image (nadir,off-nadir, referencedor unreferenced) intoENVI, then right-click
the image in the Layer
Manager and selectZoom to Layer Extent.

6If your image is georeferenced, you will not be able to record
coordinates. However, you will still be able to count features andrecord the File (x,y) values. Toggle the check boxes next to Symbol,
Label, Description, Count or Coordinates to determine which
attributes will be labeled.

GRID REFERENCE

2. Click the Feature Counting Tool button
to open the Feature
Counting dialog. Right-click on Description to turn on coordinates orFile (x,y) values for unreferenced images.
3. E nable the Gridcheck box. Bydefault, the Grid is
set to 4 x 4. You canadjust the grid sizeby entering different
values in the fields
provided.

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GRID REFERENCE

4.Click the Feature Counting Properties button
to edit the feature
properties such as the Feature Name, Font Size, Symbol, Label Position,Show Label, and Show Count.
5. C lose the Feature
Counting Properties
dialog. Add morefeatures by clicking the
Add Feature button. Change the default
Feature Name (Feature1)
in the name field.

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GRID REFERENCE

6. Select the Feature Name of the feature you want to count using thedrop-down arrow in the Feature Name field. Begin counting by clicking
on the features in your image.
7. As you count the features, click Description and enter in the attributeand associated information.
8.You can delete mistakes by highlighting the feature row(s) and clicking
the Delete Point button
to delete individually or the Delete All
Points button
to delete all.
9. To add a geographic grid, click the Annotations button
thenselect Add Grid Lines. The new grid often defaults to WGS 1984 Web
Mercator Projection.

9GRID REFERENCE
1010. You can edit the grid in theGrid Edit Properties that is
located directly underneaththe ENVI Toolbox. Here, you
can change the Coordinate
System, Text and Line Color,
XY Spacing and other gridproperties as shown in thefollowing example:

GRID REFERENCE

11. Go to the ENVI main menu and click File > Chip View To > PowerPoint
or PDF for a finished product. Also known as the Report Generation
Tool, chipping to PowerPoint allows you to utilize a variety of ENVI’s
built-in product briefing templates.

11GRID REFERENCE
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Example NADIR with Reference and Off NADIR without Reference:BAND MATH
1. Load a multispectral or hyperspectral
image into ENVI, then select Band
Algebra > Band Math from the Toolbox.
The Band Math dialog appears.
2. E nter a simple or complex mathematicalexpression using b# variables to represent
the bands you want to manipulate.
Replace # with the band number asshown in the example.

Band Math is a method used to create new raster data by performing
complex or simple mathematical functions on existing bands available in
one or more geographically referenced images. Analysts will be able tocompress data into isolated values of interest such as NDVI (NormalizedDifference Vegetation Index).
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GEOSPATIAL

Thank you for your interest in ENVI®
To continue reading the remaining chapters of the ENVI Pocket Guide
Volume 2 | Intermediate please click the following button.

DOWNLOAD THE COMPLETE POCKET GUIDEFor more information:
nv5geospatialsoftware.com
Email: GeospatialInfo@nv5.com
Phone: 303.786.9900
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