Data & Maps, for Connecticut

 

ISAT Coefficients for 2002 Land Cover

Land Cover | Coefficient Creation | The Coefficients!

The Impervious Surface Analsysis Tool (ISAT) uses land cover maps along with coefficients to estimate the amount of impervious surface in a given area, such as a local watershed. Visit the ISAT section of this website for a brief description of ISAT. Click here to download ISAT from the NOAA Coastal Services Center.

Land Cover

These ISAT Coefficients were calculated for use with the 2002 land cover data for Connecticut. This land cover was created using Landsat 30-meter satellite imagery by James Hurd as part of the Connecticut's Changing Landscape project of the Center for Land use Education and Research (CLEAR) at the University of Connecticut. An entire website is devoted to this dataset including data download (shapefile, grid and imagine format) and a thorough discussion of "what we're measuring", frequently asked questions, caution items and more.

ISAT coefficients are land cover dependent. This means that these coefficients should be used only with the landcover described above.

Coefficient Creation

Planimetric data from nine Connecticut towns was used to create the coeffiecients. The nine towns that graciously shared their excellent data are Groton, Marlborough, Milford, Stamford, Stonington, Suffield, Waterford, West Hartford and Woodbridge. In a nutshell, the highly accurate data that includes all impervious surfaces (roads, buildings, driveways, sidewalks, etc.) was compared to each of the 11 landcover classes.

The Coefficients!

Low, Medium and High refer to population density categories. If you have a shapefile with population density, choose Calculate to have ISAT choose the population category based on the shapefile. If you don't have a shapefile with population density, choose which category best fits your area. Generally, high should be used for cities and urban areas, medium should be used for surburban areas and low should be used for rural areas.

Download text file for importing straight into ISAT.
How to import? Open ArcView and turn on the ISAT extension. On the Impervious Surface Tools menu, choose Change Coefficients. Click Import and follow the prompts.

Download Excel spreadsheet.

Type them in yourself using the values below.

 

Low Population Density

Medium Population Density

High Population Density

Developed

22.67

26.07

42.26

Turf and Grass

8.58

12.09

12.87

Other Grasses and Agriculture

2.97

6.25

11.56

Deciduous Forest

1.37

2.91

5.08

Coniferous Forest

1.00

3.17

14.98

Water

0.46

0.77

4.25

Non-forested Wetland

0.48

2.29

5.98

Forested Wetland

0.46

1.03

1.20

Tidal Wetland

3.11

1.63

1.02

Barren

8.18

12.29

19.92

Utility Right-of-way

1.20

0.80

5.52