CGIA Geospatial Imaging

. Image Processing . Feature Extraction . Visualization .

Frank Obusek

Program Manager

frank.obusek@ncmail.net

Geospatial Imaging

• Remotely sensed image data acquired from airborne and earth-orbiting acquisition systems are a source for much of the geographic information the GIS community uses today.  Expertise and tools to generate the data have previously not existed within North Carolina state government.  The Center for Geographic Information and Analysis has established Geospatial Imaging services that provides expertise to state and local government agencies that depend on up-to-date geographic information to meet their GIS needs.

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CGIA’s Geospatial Imaging• CGIA's Geospatial Imaging:

Supporting North Carolina State and Local Government Agencies with services and expertise in the application of remotely sensed image data.

– Image Processing: Processing and manipulating image data into GIS-ready formats ready for feature extraction

– Feature Extraction: Converting geospatial features from airborne and space-based imagery into usable GIS layers

– Visualization: Visualizing multiple data layers of image and GIS data in one environment

• The NC Center for Geographic Information & Analysis, a receipt-funded program in the Department of Environment and Natural Resources (DENR) (LINK TO DENR SITE) is the lead organization in state government for geographic information systems (GIS). Through a NASA funded research grant, CGIA has developed the expertise and operational capacity to obtain and use remotely sensed data and image processing technology to help support the operational requirements of state and local government agencies in North Carolina. 

CGIA’s Geospatial Imaging• Remotely sensed image data provides a timely

cost-effective resource to derive GIS data• Defining methods to extract GIS information for

multiple applications • Helps support the daily operational programs of

state and local government agencies

. I m a g e P r o c e s s i n g . F e a t u r e E x t r a c t i o n . V i s u a l i z a t i o n .

CGIA’s Geospatial ImagingServices• Image Processing• Feature Extraction• Visualization

. I m a g e P r o c e s s i n g . F e a t u r e E x t r a c t i o n . V i s u a l i z a t i o n .

Image Processing

• Image processing involves the processing and manipulation of aerial photography and satellite imagery into GIS-ready image formats.  To accurately derive geospatial information from image data, it is critical that imagery be properly registered, enhanced and prepared.

CGIA’s Geospatial ImagingImage Processing Services• Format Conversion• Geo-registration• Orthorectification• Image Reprojection• Image Enhancement• Image Mosaics & Clipping• Stereo Model Creation

. I m a g e P r o c e s s i n g .

Feature Extraction• Features visible in aerial photography and

satellite imagery provides a valuable source of GIS data.  Users are able to take advantage of the increased availability of higher-resolution imagery to extract useful information. However, extracting impervious surface or land cover data using traditional pixel-based classifiers poses challenges.  Feature extraction tools that incorporate image texture and spatial context classifiers better permit the conversion of these features into a GIS environment.

CGIA’s Geospatial ImagingFeature Extraction Services• Man-made features• Natural features• Landcover• Change Detection

. F e a t u r e E x t r a c t i o n .

Geospatial Imaging Workflow1.) GIS-ready Image Data

County Orthorectified Aerial Photography

3.) GIS Layers

Impervious Surfaces, LandcoverTree Type, Urban Green Space, etc

2.) Feature Extraction

Semi-automated Feature Extraction:Uses Spatial Context, Image Texture,

Multiple layers of data, Existing GIS layers

Visualization

• Visualization is a powerful rendering capability to interpret geospatial relationships between objects and features extracted from imagery.  Multiple layers of data can be viewed at once.  Desktop visualization can make time in the field more efficient. 

CGIA’s Geospatial ImagingVisualization Services• Perspective views• Fly-throughs• Scenario Modeling• Veiwshed Analysis• Disaster Planning

. V i s u a l i z a t i o n .

Technical Support

• Technical Support Services offers a resource of expertise to state and local government agencies interested in the utility and  benefit of remotely sensed data products. Outreach is a key component of CGIA’s future design of image-derived geospatial products and the campaign to assist NC state and local government agencies in the education to use image-derived geospatial products.

CGIA’s Geospatial ImagingTechnical Support Services• Workshops• Project Support• Software Support• Applications Research• Project Development

. S u p p o r t .

Geospatial Imaging Applications & Demonstrations

Geospatial Imaging Workflow1.) GIS-ready Image Data

County Orthorectified Aerial Photography

3.) GIS Layers

Impervious Surfaces, LandcoverTree Type, Urban Green Space, etc

2.) Feature Extraction

Semi-automated Feature Extraction:Uses Spatial Context, Image Texture,

Multiple layers of data, Existing GIS layers

Stormwater Billing: Impervious surface area per parcel

Updating Impervious Surface DataA. B.

C. D.2002 Impervious 2004 Aerial Photography

2004 Impervious using 2002 Mask 2004 Impervious Update

Figure demonstrates the successful application of using image masking to update existing impervious surface data. The example shown here is of the Mallard Creek East annex north of Charlotte, NC. A.) Impervious surface data (yellow polygons) was generated from 30 cm resolution true color aerial photography. B.) New 2004 aerial photography was flown with 15 cm resolution. Compared to the 2002 impervious surface data, the imagery clearly shows the development of new homes. C.) Using the existing impervious surface data from 2002 as an image mask, the feature extraction method is focusing on only the new developed areas visible in the image. The orange polygon data, along side the yellow polygon data, show the new impervious surface to be added to the existing impervious surface data layer. D.) Combing the 2004 impervious surface data with the 2002 results in an updated data set that can be immediately implemented into storm water billing structure.

NPDES Phase II Stormwater• Benefit from accurate impervious surface

data in developing SW management plans

• Feature Extraction saves time and costs

• Updating impervious surface data becomes easier once it is collected

Landcover Feature ExtractionInput Data Output GIS Data

Using 1998 NC DOQQ color-infrared orthorectified aerial photography

New Bern, NC Landcover Data

Tree Type DelineationInput Data Output GIS Data

Pine – leaf on features Pine – polygons

Hardwood – leaf off features Hardwood – leaf off features

Using Orange County 2003 true color orthorectified aerial photography

Pine Hardwood

Urban Green Space DelineationInput Data Output GIS Data

Using Mecklenburg County 2002 true color orthorectified aerial photography

Downtown Charlotte, NC Urban Green Space

Mapping Development: GIS Update RevisitInput Data Output GIS Data

Using Mecklenburg County 2002 true color orthorectified aerial photography

Developing Areas

Contact Information• Contact Information

CGIA's RSP is headquartered in the DENR Asheville Regional Office and operates under normal business hours 8 AM to 5 PM eastern standard time.  Direct contact can be made using the information below.   For information, please contact RSP Manager Frank Obusek:

Telephone:: (828) 296-4605FAX: (828) 299-7043 Postal address:2090 US Highway 70, Asheville, NC 28778 Electronic mail: Frank.Obusek@ncmail.net