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Digital Aerial Photography Frequently Asked Questions

How do I place an order?

Aerial photography can be purchased online at http://www.dfwmaps.com/purchase.

What is a tile and how big are they?

In order to manage the data efficiently, the data from the flyover is separated into tiles. The tiles are imported into mapping software and mosaicked (pieced) together so they appear as one seamless image on DFWmaps.com. Each tile is 3,000 feet wide by 2,000 feet high.

What is the graphic format of the aerial photography? 

TIFF (Tagged Image File Format)

How is the order delivered?

Our fastest method of order delivery is by FTP, although each individual order has a total file size limit of 2000 MB to respect bandwith issues. If you wish to discuss a different method of delivery for your order, please contact us at gisorders@nctcog.org.

If you choose FTP, you will receive an email containing the link to the ftp location containing your data. This will occur after NCTCOG has finished processing your order. If you choose another method, such as Pickup or Express Mail, NCTCOG staff will contact you to determine the preferred media for delivery, and the estimated time to completion.

Note that the time for Pickup or Express Mail could be longer than FTP, because special arrangements must be made to copy the data to media and arrange delivery.

How long will it take to process my order?

You order will be processed in 1 to 3 business days from the time the order is placed. Delivery methods other than FTP may require additional time.

What is a .tiff?

A .tiff is a graphic image, much like a .bmp or .jpeg. The images are orthophotographs of the NCTCOG region and have assigned geographic coordinates. Rather than lay on top of one another, TIFFs lay side by side.

What is resolution?

Resolution is the size of each pixel in the graphic file. Much like a television screen, aerial photography is a collection of small boxes, or pixels, each having an assigned color. Together the pixels make up an aerial photo. The smaller the pixel the more precise (clear) the orthophoto, however the file size and cost increase with the resolution.

What resolutions are available and how much do they cost? 

Aerial photography costs are based on the year flown and the resolution. The following chart summarizes the cost per tile for the years and resolutions available.

Year 3 inch 6 inch 1 foot 2 foot 4 foot 8 foot
2015 -   $36.00  $18.00  $9.00  $5.00  $3.00 
2013 -   $24.00  $12.00  $6.00  $3.00  $2.00 
2012 -   $18.00  $9.00  $6.00  $3.00  $2.00 
2011 -   -   $8.00  $5.00  $3.00  $2.00 
2009 -   $12.00  $6.00  $4.00  $2.00  $1.00 
2007 -   $10.00  $5.00  $3.00  $2.00  $1.00 
2005 -   $10.00  $5.00  $3.00  $2.00  $1.00 
2003 -   -   -   $3.00  $2.00  $1.00 
2001 -   -   -   $3.00  $2.00  $1.00 

 

What is the file size for a tile? 

3 inch = 280 MB 
6 inch = 71.5 MB 
1 foot = 17.9 MB 
2 foot = 4.5 MB 
4 foot = 1.1 MB 
8 foot = 280 KB

Where can I go to view or download samples? 

Samples of aerial photography may be downloaded via the following links.

What counties have aerial photography?

Aerial Photography and Elevation Contours Coverage Areas

2013 aerial photography is available in 6-inch resolution for Collin, Dallas, Denton, Tarrant and Rockwall counties and portions of Hunt, Kaufman, Ellis, Johnson, Hood,  Parker and Wise counties.

2011 aerial photography is available in 1-foot resolution for Collin, Dallas, Denton, Rockwall, and Tarrant counties and portions of Ellis, Hood, Kaufman, Johnson, Parker and Wise counties.

2009 aerial photography is available in 6-inch resolution for Collin, Dallas, Denton, Rockwall, and Tarrant counties and portions of Ellis and Johnson counties.

2007 aerial photography is available in 6-inch resolution for all 16 counties in the NCTCOG region.

2005 aerial photography in 6-inch resolution is available for the following eight counties: Collin, Dallas, Denton, Ellis, Kaufman, Navarro, Rockwall and Tarrant.

2003 aerial photography is available in 1-foot resolution for all 16 counties in the NCTCOG region. Orthos are also available in 6-inch resolution for Collin, Dallas, Denton, Ellis, Kaufman, Navarro, Rockwall, and Tarrant counties.

2001 aerial photography is available in 1-foot resolution for the following 11 counties: Collin, Dallas, Denton, Ellis, Hunt, Johnson, Kaufman, Navarro, Rockwall, Somervell and Tarrant.

Where can I view the specifications? 

What is the accuracy of the aerial photography? 

The aerial photography meets National Map Accuracy Standards at a map scale of 1 inch = 200 feet (1:2400). The photo scale is 1' = 1500' (1:18000).

Can aerial photography be certified for legal purposes?

An aerial image can be certified as a NCTCOG product only. Certification costs $50 per item and must be done in person at NCTCOG by a notary public. Contact Alice Webster at 817-695-9140 for more information.  To certify the accuracy of the aerial image, contact the company which flew the aerials (see below).

Can TIFF files be used in AutoCAD or Microstation?

Yes, if the software version can read a TIFF file with an associated world (.tfw) file.

Who flew the aerial photography? 

2001 - Vargis, LLC
2003 - Pixxures Inc. and Dallas Aerials Surveys Inc. 
2005 - Bohannan Huston
2007 - Bohannan Huston
2009 - Bohannan Huston
2011 - Sanborn

What time of year is the aerial photography taken? 

Aerial photography is flown in January through March.

Are the street names that appear on DFWmaps.com on the aerial photography? 

No. These street names are provided by Microsoft Bing Maps and are not included on NCTCOG aerial photography.


  

 

 
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