Powerpoint Presentation that I presented at the Florida Academy of Science and Georgia Academy of Science Joint Conference held in Jacksonville, FL March 14th and 15th of 2008
REGION CLASSIFICATION AND CHANGE DETECTION USING LANSAT-8 IMAGES
Digital Ortho Image Creation of Hall County Aerial Photos
1. Authors:
Michael Adams
Patrick Taylor
J.B. Sharma
Institute of Environmental Spatial Analysis
2. The Hall County National Resource Conservation
Service (NRCS) has several sets of historic aerial
imagery
The purpose of this project was to digitize these images
such that the public can utilize them for perpetuity
This project outlines the methods used in digitizing,
geo-referencing, ortho-rectifying, and mosaicking a set
of thirty-five images taken October 12, 1980
This project was made possible by support from the
Institute of Environmental Spatial Analysis at
Gainesville State College and from a grant provided by
the Georgia View Consortium
3. It is of utmost importance to preserve the vast
number of vintage aerial photographs that have
been taken over the last century
These air photos are a clear recollection of the land
as it was at that moment in time
We can use this data to increase our understanding
of key features of the land, including forests,
watersheds, agricultural, and urban areas
The ability to use this imagery to study temporal
changes of land has grown tremendously as the
technology and software has advanced
4. approximately 394
square miles of land
split by the
Chattahoochee River
and Lake Sydney
Lanier.
Population of193,277
according to the 2000
U.S. Census
5. Set of 35 Aerial images from the Hall County
NRCS taken by Harris Aerial Surveys Inc.
All reference Images from the Georgia Spatial
Data Infrastructure (GSDI)
1. 2 meter resolution National Agriculture
Imagery Program (NAIP) Hall County
Mr.sid file 2006 leaf on image
2. 1999 Digital Elevation Model with a 30m
resolution
7. Converting an analog image into a digital
format
Images scanned at 300 dots per inch(dpi)
Each image was 24” x 24”
We outsourced this part of the project to
a local commercial printing company
because we needed a large format
scanner to handle this size imagery
8. Assigning Representation of the
coordinates of a X, Y, and Z planes
standard geographic
reference system to a
geographic feature.
In the X and Y Planes
The X, Y, and Z planes
are perpendicular to
one another
9. To correct an aerial photo for
topographic relief, lens distortion,
and camera tilt; to make the image
true to scale as if it were a map
Ortho corrected images are
corrected for changes in the Z plane
10. A sports stadium in downtown Toronto before and after
rigorous orthorectification (Imagery courtesy of DigitalGlobe)
Image Distortions
11. Autosync Extension of Erdas Imagine 9.1
Direct Linear Transform method:
This method creates Ground Control Points
between Spatial Coordinates and Image
Coordinates
15. Smoothing Filter applies a blurring filter
along each side of the newly generated
cutlines
Feathering Filter softens the edges of the
cutline by blending all of the pixels within a
fixed distance
Color Balancing removes brightness
variations found across the mosaic
Histogram Matching creates a new histogram
for all of the images to be mosaicked by
matching them to one another
16. Image is ready for use in a GIS system
for land use analyses or other research
17. 1. Digitization of Images 1. Professionally scanned
2. Data Management 2. Created standard file
structure
3. Computing power 3. Each image 350MB or >
final mosaic 4.24 GB
(Terabyte server)
4. Root Mean Square Error 4. Use .5 pixel error and
swipe tool to visually
interpret error
5. Mosaic 5. Mosaic
lighting conditions/lens flare color balancing, histogram
transition from image to matching
image created cut-lines for
feathering & smoothing
filters
20. Project Funded by a grant from The
Georgia View Consortium
These images are now useful for
scientific analyses
The Hard Copy of these images are now
preserved for future generations
22. Aronoff, Stan, 2005, Remote Sensing for GIS Managers, ESRI Press, Redlands, California, 487 p.
Marzan, G. T. and Karara, H. M. 1975. A computer program for direct linear transformation
solution of the colinearity condition, and some applications of it. Proceedings of the Symposium
on Close-Range Photogrammetric Systems, pp. 420-476. American Society of Photogrammetry,
Falls Church.
2007, Erdas Imagine 9.1 Field Guide Volume One, Leica Geosystems Geospatial Imaging, LLC,
http://gi.leica-geosystems.com/documents/pdf/FieldGuide_Vol1.pdf (March 7, 2008).
2007, Erdas Imagine 9.1 Field Guide Volume Two, Leica Geosystems Geospatial Imaging, LLC,
http://gi.leica-geosystems.com/documents/pdf/FieldGuide_Vol2.pdf (March 7, 2008).
Kwon, Y.-H. (1994). KWON3D Motion Analysis Package 2.1 User's Reference Manual. Anyang,
Korea: V-TEK Corporation. http://www.kwon3d.com/theory/dlt/dlt.html (March 12, 2008).
