Georeferencing and GoogleEarth

Francisco Olivera, Ph.D., P.E.Celso Ferreira

Department of Civil EngineeringTexas A&M University

OverviewGeoreferencing using ArcGIS

Visualizing data in Google Earth

Georeferencing:Acquiring a digital image

Importing images in ArcGIS

Defining control points

Resampling the image

Acquiring Imagese.g.: Brazos County Aerial Photos from 1940

Georeferencing Concepts

Source: ESRI Help

Georeferencing Concepts

Source: ESRI Help

Real World Coordinates

Original Image Raster

Georeferencing GoogleEarth Images

Find control points in Image

Get coordinates for each point

Use Georeferencing toolbar for adjusting the image

Demo: Georeferencing Images using ArcGIS

Exercise Outline:Goal: Find Reed Arena geographical location using a 1940 aerial photograph

• Load the georeferenced layers• Load the 1940 Image• Georeference the image• Delineate a polygon around Reed

Arena

GoogleEarth:

GoogleEarth:Preparing the data in ArcGis

Exchanging data:Keyhole Markup Language (KML) is an XML-based language schema

Generating KML files from ArcGis

Importing KML files in GoogleEarth

Preparing the dataGeneral geoprocessing procedures

Identify, clip, intersect, union…

Make sure to “clean up the data” and select appropriate area

Generating KMLConversion Tools>>To KML>>Layer to KML

Importing KMLIn GoogleEarth Open KML

Examples – Watershed delineation

Examples – Watershed delineation

Demo: Visualizing data using GoogleEarth

Data available from:Dr. Olivera home page / Geomatics in Civil Engineering

(CVEN 423) / Spring 2009https://ceprofs.civil.tamu.edu/folivera/CVEN423/

Spring2009/home.htm

Questions ?