Multi-Sensor Land CoverMapping Using GEOBIA and Exploring E. Coli Correlations

Cassie TamblynGainesville State CollegeFall 2012

OBJECTIVE Use geographical object based

image analysis (GEOBIA) to determine if there is a correlation between land cover classification and E. coli levels within the Flat Creek Watershed and its subwatersheds

BACKGROUND GEO-Object Based Image Analysis

Looks at images as groups of objects rather than pixels

More like how we see imagesCan use many layers to delineate objectsYields more accurate results (when applied

properly) E. Coli contamination

Easy way to measure fecal contamination100 cfu’s allowed during spring months for

fishing waters

DATA USED 15 LiDAR tiles (1.5m posts), 2010 42 CIR tiles (0.1524m spatial

resolution), 2010 Flat Creek watershed boundary &

subwatershed boundary shapefiles (created using ArcHydro)

E. Coli measurements during March & April 2012 (from Upper Chattahoochee Riverkeepers)

SOFTWARE USED ArcHydro

Delineate watershed Quick Terrain Modeler

Create nDSM (DSM-DEM) ERDAS Imagine

Mosaic imagery eCognition Developer

Develop and process rule set ArcMap

Develop Map Layout

AREA OF INTEREST Flat Creek Watershed (divided into 5

subwatersheds) Total area = 20,000,000 m2

Flat Creek starts in Gainesville and flows in a southwesterly direction to Lake Lanier

One of the most impacted streams of Georgia Most of land within watershed is covered by

impervious surfaces Industrial district contains chicken processing

plants and other factories Some agricultural land

AOI

RULE SET

POST PROCESSING RULE SET After processing entire AOI on the

server & merging the data again….

RESULTSArea by Land Classification for Flat Creek Watershed:Class Pixels Area (sq m) Percent of TotalBuildings 8.506E+07 1.976E+06 9.95Grass 1.399E+08 3.250E+06 16.37Trees 1.673E+08 3.885E+06 19.56Impervious 4.627E+08 1.075E+07 54.12Total 8.550E+08 1.986E+07 100.00

RESULTS for SUBWATERSHEDSArea by Land Classification for Each Subwatershed:

Class Pixels Area (sq m) Percent of Total E. Coli (cfu)Buildings 2.267E+07 5.266E+05 7.33 50Grass 6.051E+07 1.405E+06 19.57 155Trees 8.068E+07 1.874E+06 26.09 50Impervious 1.454E+08 3.376E+06 47.01 100Total 3.092E+08 7.182E+06 100.00 88.75

Subwatershed 1 (Southern/Old Flowery Branch Rd.)

Class Pixels Area (sq m) Percent of Total E. Coli (cfu)Buildings 1.762E+07 4.093E+05 9.68 155Grass 2.731E+07 6.342E+05 14.99 995Trees 4.328E+07 1.005E+06 23.76 260Impervious 9.392E+07 2.181E+06 51.57 310Total 1.821E+08 4.230E+06 100.00 430

Subwatershed 2 (Western/Dixie Dr.)

Class Pixels Area (sq m) Percent of Total E. Coli (cfu)Buildings 3.616E+07 8.398E+05 12.03 625Grass 3.506E+07 8.143E+05 11.66 730Trees 5.164E+07 1.199E+06 17.18 600Impervious 1.777E+08 4.128E+06 59.13 610Total 3.006E+08 6.981E+06 100.00 641.25

Subwatershed 3 (Northern/Atlanta Hwy.)

Class Pixels Area (sq m) Percent of Total E. Coli (cfu)Buildings 6.883E+06 1.599E+05 5.57 375Grass 1.657E+07 3.849E+05 13.42 995Trees 1.821E+07 4.229E+05 14.74 610Impervious 8.187E+07 1.902E+06 66.27 1460Total 1.235E+08 2.869E+06 100.00 860

Subwatershed 4 (Eastern/Dorsey St.)

Class Pixels Area (sq m) Percent of Total E. Coli (cfu)Buildings 4.201E+06 9.757E+04 7.22 2500Grass 9.452E+06 2.195E+05 16.25 605Trees 1.299E+07 3.017E+05 22.33 260Impervious 3.153E+07 7.323E+05 54.20 3105Total 5.817E+07 1.351E+06 100.00 1617.5

Subwatershed 5 (Central/Industrial Hwy.)

CORRELATION?

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E. coli (cfu) vs. Percent Impervious

Percent Impervious

CORRELATION, cont.

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5

10

15

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E. coli (cfu) vs. Percent Grass

Percent Grass

ANALYSIS No correlation was found by this

assay in this watershed No manual editing was done which

may improve accuracy which could in turn improve correlation

Point sources could be added to correlation factor

Questions? Thank you!