COLOR ME ORTHOED Gary Lobdell Photogrammetric Account Manger Certified Photogrammetrist The Sidwell Company

COLOR ME ORTHOED ORTHOS, NOW WHAT? Review of the Image 2005 Orthophoto Products DEM vs. DTM How Will I View Them? What Features Will I Be Able to Identify? Custom Image Displays

2005 ORTHO PROJECT Image Products 1 Meter County Mosaic 1 Ft Color Ortho (79 Counties) ½ Ft Color Orthos (13 Counties) 1 Meter Color IR Data Products Digital Surface Model (DSM) Digital Elevation Model (DEM)

2005 ORTHO PROJECT Image Deliverables Type & ResolutionFormat/Tiling 1 Meter County MosaicMrSid – Single County Tile 1 Ft Color Orthos (79 Counties) TIF – SPC Grid Tiles ½ Ft Color Orthos (13 Counties)TIF – SPC Grid Tiles 1 Meter Color IRUSGS Quarter Quadrangle (3.75 Minutes)

DATA PRODUCTS DSM – Digital Surface Model Auto-correlated Elevation Data Includes Above Ground Features 1 or 2 Meter Posting (Terrain Dependant) DEM – Digital Elevation Model Processed Subset of the DSM Near Bald Earth Elevation Set Can Support Generation of 5 Foot Contours

DEM vs. DTM Digital Elevation Model (DEM) Simple or Generalized Model of Earth Surface Use is limited to its original intent May Contain Points or Points & Minimal Breaklines Digital Terrain Model (DTM) Complex Model of Earth Surface Multiple Uses within the Accuracy Expectations Will Contain Points & Breaklines

WHAT CAN I SEE? ½ Foot Resolution High Level of Detail Visible Wide Variety of Uses 1 Foot Resolution Good Level of Detail Visible General Variety of Uses 1 Meter Resolution Good for Big Picture Studies or Viewing a Large Area

What Scale Can I View? ½ Foot 1 Foot 1 Meter Use Imagery At Its Optimal Scale The Optimal Scale Is Approximately 200 Times The Pixel Resolution Can Often Be Viewed Up To 100 Times The Pixel Resolution Match The Use To The Resolution And View Scale Need At Least 4 Pixels To Represent An Identifiable Feature

WHAT SCALE CAN I VIEW? ½ Foot 1 Foot 1 Meter Expected Range of View Scales 1”=100’ 1”=200’1”=650’ 1”=50’ 1”=100’1”=325’

GOT PIXELS? You Need Enough Pixels To Identify The Object A Car Is Approx 5 X 10 Feet At ½ Foot Res – 200 Pixels At 1 Foot Res – 50 Pixels At 1 Meter Res – 3 to 8 Pixels

GOT PIXELS? Identifying Manholes ½ Foot 1 Foot 1 Meter

RULES DON’T ALWAYS HOLD UP Power Lines Shouldn’t Be Visible

Are Fences Are Too Narrow? RULES DON’T ALWAYS HOLD UP

CAN I COLLECT NY OWN DATA? Data is Best Collected by a Service Provider Stereo (3D) Data Collection is Most Accurate Collected from the Original Photography Professional Data Technicians

Things Are Not Always Where They Seem To Be Only on a True Ortho are the Building Tops Over the Base Manholes are Not Always Visible Pole Locations are Very Often Obscured CAN I COLLECT NY OWN DATA?

DATA STORAGE Storage Requirements by Resolution Image Set Per Sq MiTile SizePer Tile 1 Meter Color 8 MBCounty (MrSid)Approx 170 MB 1 Foot Color 84 MB2500 X 2500 Ft19MB ½ Foot Color 335 MB 2500 X 2500 Ft75MB If 2500 X 2500 Pix19MB

VIEWING ORTHOS Current CAD and GIS Software Will Have Image Viewing Capability Built In Image File Viewers ESRI Products MicroStation AutoCad Lizardtech Offers Free Viewers for MrSid Files

THAT SPECIAL PROJECT Customize Your Imagery Court Cases Zoning Issues Land Use Environmental Issues

PROJECT SPECIFIC IMAGES Select a Portion of an Image and Add Text

PROJECT SPECIFIC IMAGES Create an Image Customized for Your Display