ENVI User Group Spring MeetingVIS li 2012VISualize 2012

MODIS NDVI Time Series Classification in ENVI for CropClassification in ENVI for Crop

Mapping and Performance pp gEstimates Tatiana Nawrocki

June 18 - 19, 2012

h d d b l l d l f fThe process discussed below relied on ENVI classification ofMODIS NDVI time series (multi‐band imagery datasetsassembled from single‐band raster datasets). Unlike inassembled from single band raster datasets). Unlike inconventional multi‐spectral imagery, the bands consisted oftemporal layers. ENVI ISODATA classifier treated temporalstacks as multi‐spectral datasets. The classification revealedlocations of crops, which displayed similar seasonaldevelopment curves (“temporal” signatures) Digitaldevelopment curves ( temporal signatures). Digitalnumbers (NDVI values) in each temporal “band” in aseasonal stack provided crop performance metrics atspecific vegetation stages of each classified crop and servedfor comparing their performance between differentseasonsseasons.

Normalized Difference Vegetation Index (NDVI)

8%50%

0 72g

NDVI = (NIR — VIS)(NIR + VIS)

0.72

0.14

(0.40 — 0.30)/(0.40 + 0.30) = 0.14 (0.50 — 0.08)/(0.50 + 0.08) = 0.72

Synthetic “spectral” signatures of a multiband NDVI image stack simulate NDVI dynamics during crop vegetation cycle 

( ) ( ) ( ) ( )

y g p g y

MODIS/NDVI Time Series Database: Crop Explorer 

Compare seasonal cropseasonal crop conditions by countries andcountries and 

regions

Blended performance metrics of different cropsof different crops

Assemble MODIS NDVI temporal stacks representing seasonal conditionsrepresenting seasonal  conditions

Band Start Date End Date1 17-Nov 2-Dec2 3-Dec 18-Dec2 3 Dec 18 Dec3 19-Dec 3-Jan4 1-Jan 16-Jan5 17-Jan 1-Feb6 2-Feb 17-Feb

2008        2009        2010        2011

6 2-Feb 17-Feb7 18-Feb 5-Mar8 6-Mar 21-Mar

Classify seasonal NDVI image stacks in ENVI

Non‐supervised classification within 

Review band statistics and select crop types for comparative 

cropland maskp yp p

seasonal crop performance analysis 

ClVI Classes

ND

R i t ti ti f l t d l

Temporal bands

Review statistics for selected classes

Review temporal band statisticsReview temporal band statistics

2007/2008 2008/2009

2009/2010 2010/2011

Compare peak period histograms2007/2008 2008/2009

2009/2010 2010/20112009/2010 2010/2011

Temporal Band 6 – Early FebruaryTemporal Band 7 – Late February‐March

Crop performance varied by locationsCrop performance varied by locations

(winter season)( )

Seasonal crop production could be related to spatial i f ll d l f iratios of well and poorly performing crops 

Compare spatial patterns of seasonal crop performanceperformance

Compare crop areas by different p p yperformance classes, 2007 – 2011 Rabi

crop seasons Pakistancrop seasons, Pakistan

Crop performance in 2011/12

Pakistan MODIS NDVI time series analysis showed inferior f d d d f ll f iperformance and reduced areas of well performing crops 

in 2011/12 compared to previous season

MODIS NDVI time series geospatialseries geospatial analysis and classificationclassification methods were 

explored with theexplored with the goal to identify 

locations of majorlocations of major crops in the 

European part ofEuropean part of Russian Federation in 2011 seasonin 2011 season

Similar agro‐climate conditionsClassification was more successful 

g

within a smaller window of three most important winter grain regions 

(Krasnodar, R i l Rostov, and 

Stavropol). 

Regional mask

Review spectral profiles seasonal crop f f i i f l d i lperformance of winter grain for selected pixels

Image band16‐day NDVI dataset    16‐day NDVI dataset 

l b dTemporal bandImage band 

Start date  End date  Image band  Start date  End date 

Band 1  6‐Apr  21‐Apr  Band 5  9‐Jun  24‐Jun Band 2  22‐Apr  7‐May  Band 6  25‐Jun  10‐Jul B d 3 8 M 23 M B d 7 11 J l 26 J l

Temporal band

Band 3  8‐May 23‐May Band 7 11‐Jul 26‐JulBand 4  24‐May  8‐Jun  Band 8  27‐Jul  11‐Aug 

 

Classified crops, 

Southern Russia

Locations of major winter grains bywinter grains by performance categories in 

Krasnodar, Rostov, and Stavropol regions, 

iRussia, 2011

0 80

0.90

0 40

0.50

0.60

0.70

0.80

0.20

0.30

0.40

6‐Apr 21‐Apr 6‐May 21‐May 5‐Jun 20‐Jun 5‐Jul 20‐Jul 4‐Aug

Good Moderate

onficatio

Verif

REGION NAME Reported winter wheat, thousand ha, 2011

Classified winter wheat, thousand ha

Agreement%

Stavropol'skiy kray 1724.2 1213.3 70.4%Rostovskaya oblast' 1974.7 1584.6 80.2%Krasnodarskiy kray 1306.7 1082.7 82.9%Respublika Adygeya 81.6 60.7 74.4%

 

Classifications of reduced temporal stackspCrop performance curves obtained during a reduced b i i d ll dobservation period allowed identifying well performing 

winter crops (class 9), however moderatelyhowever, moderately 

performing winter crops (classes 8 & 7) overlaid with  

summer crops.summer crops. 

REGION NAME Well performing crop area, thousand ha Moderately performing crop area, thousand ha

5-band 9-band 5-band 9-bandStavropol'skiy kray 928.2 854.7 559.8 358.6

Rostovskaya oblast' 325.5 446.4 1402.6 1138.2

Krasnodarskiy kray 1021 6 930 8 758 0 151 9

8‐band 8‐band

Krasnodarskiy kray 1021.6 930.8 758.0 151.9

Conclusions:Conclusions:MODIS NDVI time series classification was suitable for categorizingcrop seasonal performance. These results could potentially become

dditi l f i f ti f f ti i l i ld dan additional source of information for forecasting regional yield andproduction trends.

Limitations:Classifications within large, non‐uniform regions delivered lessdistinct separation between winter grains and other crops.Classifications derived from reduced (5‐band) temporal stacksClassifications derived from reduced (5 band) temporal stacksdelivered suitable results for well performing crops only. Delayedwinter crops and summer crops did not separate.

DisclaimerDisclaimer:The contents contained in this presentation do not necessarilyreflect the work and/or opinions of the USDA and its authorities.