Posts Tagged ‘2009AerialsFourInch Service’

Accessing Aerial Photos within AutoCAD using ArcGIS for AutoCAD and the mapiinsert Command

October 1, 2009

At the Port of San Diego, our CAD Designers and Mapping Technicians can access our new 2009 4-inch aerials photos within AutoCAD in 2 ways. Each has their own advantages and disadvantages. Understanding these pros and cons empower our CAD designers to be more efficient and effective. I suggest any substantial project would be best approached by utilizing both methods.

ArcGIS for AutoCAD- Great for everyday workflow
Pros
fast
access to content on other ArcGIS Servers, including ArcGIS Online
easy to create image with defined extent
Cons
Best resolution not guaranteed at all scales

mapiinsert command – Printing
Pros
best resolution guaranteed at all scales
CAD users more familiar
Cons
slow

As a footnote, it should also be mentioned that ArcGIS for AutoCAD has another powerful component; the ability to create GIS attribute data within AutoCAD. As the PortGIS Program matures it will require us to gain more information about our features which originate in AutoCAD. What is the material/width/flow capacity of this pipe? Collecting this type of attribute data will allow us to 1) display and symbolize this data across the enterprise and 2) do spatial analysis, such as identifying where weaknesses might be in our utility infrastructure.

ArcGIS for AutoCAD can be downloaded from ESRI at the link below.
http://www.esri.com/software/arcgis/arcgis-for-autocad/download.html

GeographyHuntingBinLaden Zen
and another

Introducing the 2009AerialsFourInch Service

May 29, 2009

Aerials are an integral part of any well rounded Geographic Information System. Aerials can be used as a great base to provide a context for other data, as part of a quality control effort, or as the source to create new data.

Our new 2009 aerials were flown between 11:20AM and 12:30PM on April 17th, 2009. They are 4 inch resolution meaning each pixel correlates to 4 inches by 4 inches (16 square inches) on the ground. Our new aerials are the highest quality I have ever worked with. They are on-par with the best aerials available today. Below is a table comparing some of the variables between the 3 main aerials we use here at the Port.

Aerial Service: I3_Imagery Prime_World_2D 2005AerialsHalfFoot 2009AerialsFourInch
Source: ArcGIS Online Port Port
Date Taken: 3/15/2008 in Port Area 2005 4/17/2009
Coverage: Worldwide 52.5 Sq. Miles covering Port Tidelands 48.7 Sq. Miles covering Port Tidelands
Resolution: .3 Meters (≈1 Foot) in Port Area Half Foot Four Inch
Ground Pixel Size: 12 x 12 = 144 Sq Inches 6 x 6 = 36 Sq Inches 4 x 4 = 16 Sq Inches

Below are 2 images showing measurements of one side of each pixel.

2005 Pixel Measurement

2005 Pixel Measurement

2009 Pixel Measurement

2009 Pixel Measurement

This is all great, but how does this correlate to the real world? Below are the 3 images of the Administration Building Parking lot. As you know the parking lot was recently repaved and reorganized.

2003 Parking Lot

March 2008 .3 Meter Resolution

2005 Parking Lot

2005 Half Foot Resolution

2009 Parking Lot

April 2009 Four Inch Resolution

Along with our parking lot there have been other changes on or around the Port tidelands since 2005, including the new Hilton between the Convention Center and Tenth Avenue Marine Terminal.

Left 2005 - Right 2009

Left 2005 - Right 2009

We have set up a web application where Port employees can examine the new aerial photos. You can get to this web application by clicking on the 2009 Aerials button at the PortGIS Resource Center. They are much larger images and therefore take a second or two more to render on your screen. Feel free to turn on and off layers in the “Map Contents” area. We hope to include them in the other PortGIS applications shortly.

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