7-10 June 2016, Colombia

McIDAS-V Tutorial 5: Normalize Difference Vegetation

Index (NDVI)

AmeriGEOSS GNC-A Workshop

McIDAS-V Tutorial 5: NDVI 1

Contents

1. Getting Started ...................................................................................................................................................1

2. Changing the Default Background Map ............................................................................................................2

3. Loading the NOAA NDVI AVHRR GeoTIFF File ..................................................................................................3

4. Loading the INPE NDVI GeoTIFF File produced from VIIRS imagery ................................................................6

1. Getting Started

McIDAS-V

McIDAS-V is a visualization and data analysis software package. This tutorial assumes that you have

limited experience with McIDAS-V. For a list of references, the following online documentation page

includes a current user’s guide, tutorials and instructional videos:

http://www.ssec.wisc.edu/mcidas/software/v/documentation.html

Tutorial Files

Download and save the provided files. The NDVI_AVHRR directory contains weekly AVHRR normalized

difference vegetation index (NDVI) data, 1 file for every 4th week. Note that the GNCA_June2016.jar file

should already be installed. If this is not the case, please refer to McIDAS-V Tutorial 1.

NDVI_AVHRR (14 files)

NDVI from INPE via GNC-A

McIDAS-V Tutorial 5: NDVI 2

2. Changing the Default Background Map

2.1 Open McIDAS-V. Recall that the two main windows are:

Data Explorer – where data is selected and layer properties are modified

Main Display Window – shows a map projection and any selected data

2.2 You can change the background map settings to your preference at any time (refer to

McIDAS-V Tutorial 1). A good start is to zoom in on the Caribbean region. If you did not save

this as your default setting, go to the Main Display window and select Projections

Predefined Caribbean. You may also change the map outline by clicking Default

Background Maps and making your changes in the Layer Controls panel.

McIDAS-V Tutorial 5: NDVI 3

3. Loading the NOAA NDVI AVHRR GeoTIFF File

3.1 These NDVI products mask for clouds. These files are in a GeoTIFF file format. Pull up the

Data Sources tab.

a) In the column on the left expand the General heading. Then select Files/Directories.

b) From the Data Type menu, select TIFF files.

c) From the Look In menu, navigate to the directory where you have saved the NDVI

AVHRR files. Here (D:\GNCA\data\NDVI_AVHRR)

d) Select a file of your choice. The last three digits in the filename correspond to the week

number in 2015. In this example we will use VHP.GO4.C07.NP.P2015005.SM.SMN.tif,

which corresponds to 26 Jan – 1 Feb 2015.

e) Click the Add Source button.

3.2 Create an image display of the NDVI data. Click on the Field Selector tab.

a) Under the Data Sources column, select the GeoTIFF filename.

b) Under the Fields column, select VHP.GO4.C07.NP.P2015005.SM.SMN.tif – Grid data.

c) Under the Displays column, select Image Display.

d) Click the Create Display button.

a

b c

d

e

McIDAS-V Tutorial 5: NDVI 4

3.3 Change the display properties under Layer Controls.

a) Click the color table button and select GNCA NDVI_black. Change the range from 0

to 0.7.

b) Add the color table to

the display image by selecting Edit

Properties… and making your changes

on the Color Scale tab. Click Apply/OK

c) To change the layer and legend

labels, select Edit Properties… and

make your changes in the Settings tab.

Click Apply

3.4 View the data in the Main Display window and zoom in on Guyana or some other location. ?

Is vegetation uniform or variable across the region?

3.5 Let’s load another file to see how vegetation changes throughout the year. Pull up the Data

Sources tab.

a) In the column on the left expand the General heading. Then select Files/Directories.

a b c d

b

McIDAS-V Tutorial 5: NDVI 5

b) From the Data Type menu, select TIFF files.

c) From the Look In menu, navigate to the directory where you have saved the files.

d) Select a different file than last time. In this example we will use

VHP.GO4.C07.NP.P2015029.SM.SMN.tif, which corresponds to 13-19 July 2015.

e) Click the Add Source button.

3.6 Create an image display of the NDVI data. Click on the Field Selector tab.

a) Under the Data Sources column, select the GeoTIFF filename.

b) Under the Fields column, select VHP.GO4.C07.NP.P2015029.SM.SMN.tif – Grid data.

c) Under the Displays column, select Image Display.

d) Click the Create Display button.

3.7 View the data in the Main Display window and zoom in on Guyana or some other location.

Compare and contrast NDVI for January and July. Is there a seasonal change? How does this

relate to precipitation?

McIDAS-V Tutorial 5: NDVI 6

4. Loading the INPE NDVI GeoTIFF File produced from VIIRS imagery

Load a different format GeoTIFF produced by INPE and available through GNC-A. The values in this

file need to be divided by 255, so a formula will be applied.

4.1 Pull up the Data Sources tab.

a) In the column on the left expand the General heading. Then select Files/Directories.

b) From the Data Type menu, select TIFF files.

c) From the Look In menu, navigate to the directory where you have saved the NDVI

AVHRR files. Here (D:\GNCA\data\NDVI_INPE)

d) Select INPE_NDVIM_20160331.tif.

e) Click the Add Source button.

4.2 Click on the Field Selector tab.

a) Under the Data Sources column, select Formulas.

b) Under the Fields column, expand the GeoTIFF Tools June 2016 and select NVDI from

INPE.

c) Under the Displays column, select Image Display.

d) Click the Create Display button and a new Field Selector window will appear.

e) Expand INPE_NDVIM_20160331.tif and select INPE_NDVIM_20160331.tif – Grid data.

Click OK.

McIDAS-V Tutorial 5: NDVI 7

4.3 Change the display properties under Layer Controls.

a) Click the color table button and select GNCA NDVI_black. Change the range from 0

to 0.7.

b) Add the color table to

the display image by selecting Edit

Properties… and making your changes

on the Color Scale tab. Click Apply/OK

c) To change the layer and legend

labels, select Edit Properties… and

make your changes in the Settings tab.

Click Apply

b

McIDAS-V Tutorial 5: NDVI 8

The NOAA AVHRR NDVI data was downloaded from this site:

ftp://ftp.star.nesdis.noaa.gov/pub/corp/scsb/wguo/data/VHP_4km/geo_TIFF/

More information can be found in the NDVI quick guide.

The INPE NDVI files are broadcast through GNC-A.

How can you use this data set combined with precipitation and surface temperature to monitor

drought?

Would you like to see both of these data sets on GNC-A?