BREAKOUT SESSION– ENVIRONMENTAL  APPLICATIONS

CONNECTICUT USER TO USER NETWORK:  COFFEE, DONUTS AND GIS – APRIL 2, 2011

See a Summary of this session.

Key Data Layers:

Topography:

Issues: Pixels (raster), Triangulated Irregular Networks (TIN), contour, point elevations

Sources: 

- 10 ft horizontal interval LIDAR data by quarter-quadrangle - http://clear.uconn.edu/data/CT_DEM/ct_dem_download.asp

- 30 m Digital Elevation Model (National Elevation Dataset) http://seamless.usgs.gov/

Example: Cromwell.sxd (open from desktop) – ArcScene application.

 

Land Cover

Usually raster, sometimes converted to feature.  Derived from satellite imagery. Commonly produced by government (public universities) so it is free.

Sources:

- Northeast: From a USGS Gap Analysis data set; very detailed as to land cover classes; can take a while to download and unzip: http://gapanalysis.usgs.gov/data/land-cover-data/

- Connecticut: http://clear.uconn.edu/projects/landscape/download.asp Small number of classes; designed for change analysis between years.

Existing Preserved Open Space:

Sources: http://www.ct.gov/dep/cwp/view.asp?a=2698&q=322898&depNav_GID=1707#Property
Example: Town of Essex Open Space: Different Data Sources – Software:ArcGIS Explorer (ESRI freeware - http://www.esri.com/software/arcgis/explorer/download.html)

Land Parcels

Usually maintained by city or town, varying quality
Source: http://www.ct.gov/dep/cwp/view.asp?a=2698&q=322898#Property Statewide (mostly) parcel layer from mid to late 2000s

Hydrography

Best layer is still off 1:24,000 scale 7.5 min. series topographic maps. Scale results in generalization and many have been buried, put in culverts etc.

Source: http://www.ct.gov/dep/cwp/view.asp?a=2698&q=322898#Hydrography

 

Wetlands

Two Sources: Soils geodatabase from DEP; requires a relational join between the feature table and the SOILS_POLY_DATA table (lookup table) on MuSym field.  Wetland field is CTWET. http://www.ct.gov/dep/cwp/view.asp?a=2698&q=322898#Soils  Second source is more difficult to deal with, National Wetlands Inventory . Download from http://www.fws.gov/wetlands/Data/DataDownload.html
Example: SoilsInAshford.pmf – ArcReader Application

 

Bedrock and Surficial Geology

Surficial - glacial and post glacial materials. Bedrock – below surface, of less value to most environmental questions. Source: http://www.ct.gov/dep/cwp/view.asp?a=2698&q=322898#Geology

 

Natural Diversity Database and Critical Habitats

NDDB, approximate locations (.5 m buffers) of endangered and threatened species. Critical Habitat - locations of 27 critical habitat types (most are flood plain forests) from state plan for wildlife conservation. 

Source: http://www.ct.gov/dep/cwp/view.asp?a=2698&q=322898#EndangeredSpecies

 

Orthophotography

Best accessed through image services from CT ECO (Connecticut Environmental Conditions OnLine).

Source: http://cteco.uconn.edu/map_services.htm

 

Oblique Aerial Photography

From Pictometry Corp.  Public access to state’s data is limited (court case pending).Web access to older, less detailed information at http://www.bing.com/maps/

Example: Ortho.pmf – ArcReader application

 

Applications:

Clipping

Removal of a small area from a larger one, the cookie cutter function.
Example: ClipExample.mxd – ArcGIS Desktop application

 

Select by Attribute/Location

Structured Query Language attribute queries and spatial queries.
Example: SelectByAttribute.mxd – ArcGIS Desktop application

 

Inland Wetlands and Watercourse Map

Rapid development of a draft, unofficial wetlands map
Example: InlandWetlandMap.mxd - ArcGIS Desktop Application

Gap Analysis

Locating forest type gaps in preserved open space
Example:GapAnalysis.mxd