Pennsylvania's Aerial Imagery Program Frequently Asked Questions (FAQ)
Why is Pennsylvania flying new imagery?
The last statewide imagery collection effort was spearheaded by the Department of Conservation and Natural Resources, which began in 2003 and ended in 2008. The current imagery available to the commonwealth is more than ten years old. There have been individual areas of the commonwealth flown more recently than ten years; however, an overall statewide dataset has not been undertaken since 2008.
In 2017, the Pennsylvania Emergency Management Agency (PEMA) worked with the Pennsylvania GIS Community to develop a Statewide
Next Generation 911 (NG911) GIS Strategic Plan. As part of the plan, PEMA solicited feedback from county GIS professionals across the commonwealth to determine what services or assistance, if provided by PEMA, would be the most beneficial to the local GIS community.
The most common response was the provisioning of remote-sensing data on a regular, recurring schedule, to provide a foundation for the creation and maintenance of NG911 foundational data.
PEMA worked with the 911 Advisory Board to secure funding for the statewide imagery contract to procure new and updated imagery for the commonwealth to be updated on a recurring basis.
Who is collecting the orthoimagery (who is flying)?
PEMA executed a contract with Quantum Spatial in March of 2018 for four years, worth $5.3 million. In addition, PEMA built three one-year optional renewals into the contract, allowing the contract to have the potential of seven years.
Who is QA/QCing the data?
PEMA executed a contract with Dewberry for four years, worth $1.1 million.
Is the imagery leaf-off or leaf-on?
The data is being collected with the leaves off the trees. This is what the counties and end-users have asked for.
What are the time and weather conditions for the acquisition?
The weather conditions need to be ideal and when the sun angle meets or exceeds 30 degrees.
What are the altitude specifications?
The Leica ADS100 sensor used to collect the data can achieve a ground sample distance of six inches by maintaining an average flight altitude above mean terrain (AMT) at roughly 6250 feet.
What is the current status of the orthoimagery?
View or download the
PEMA Ortho Production Status Map (PDF).
What is the current status of the acquisition of new imagery?
View or download the
PEMA Acquisition Map (PDF).
Where counties are partially flown, is it possible that the imagery will span two different flight seasons?
Since the flights were started in 2018, it is possible that some counties were flown in the spring of 2018 and finished in the fall of 2018. It’s also possible that some counties were flown in the fall of 2018 and the spring of 2019, and it will be possible that some counties will be flown in spring 2019 and fall 2019.
After Year 1 is complete, the expectation is that county data will be collected all within the same flying season.
Why do some areas need to be reworked?
In some instances, the imagery collected did not meet the requirements of leaf-off, no snow cover, etc. and these tiles will need to be reflown and reprocessed.
Please note -- some exceptions were made where extraneous factors did not inhibit the imagery (i.e., snow pile on a parking lot).
Why does my county have a big gap or hole in the tiles acquired?
As the first round of flights are occurring in 2018 and 2019, there are areas that appear as gaps or holes in the data. Sometimes this is due to ground conditions, weather conditions, or restricted airspace. These areas will be flown as soon as possible.
When will orthoimagery be collected for my county?
Environmental conditions will determine when and where imagery will be collected during the initial statewide collection.
Where can I access the data?
The orthoimagery data can be accessed at
Pennsylvania Spatial Data Access (PASDA). Once on PASDA’s website, you can click the “Imagery” icon, or you can search for PEMA Orthoimagery.
All of the datasets are compiled and are available as tile mosaics or web services for the entire county. You can also use PASDA’s
Imagery Navigator to download specific tiles.
The tiling system is the same as it was for the PAMAP Program, but to avoid confusion, the tile name has "PEMA_2018" at the end of the file name. You can directly access the
PEMA North Tile Index and
PEMA South Tile Index.
Does the orthoimagery have metadata?
All datasets include FGDC-compliant metadata, which can be found on the PASDA website for each dataset under the Metadata link (as shown in the image below).
In addition, each county is provided a shapefile containing as-flown photo information, which includes additional flight-specific details.
What is the project update cycle?
Below is the estimated out year collection cycle and subject to change at any point.