An aerial photograph is a picture usually
taken from an airplane. It could be taken from directly overhead or at an
Aerial photography has many different uses. Because it provides data and a
perspective that is otherwise elusive, there are applications in academic research,
resolving legal disputes, tracking genealogy, planning real estate development,
and much more.
Government agencies, construction contractors, financial investors, legal professionals,
and environmental businesses use aerial photography quite extensively when performing:
» Environmental due diligence and site assessments
» Allocation of environmental liability
» Reclamation obligations
» Historical site documentation
» Vegetation growth tracking
» River and runoff trends
» Building and development growth
Historical Aerial Photographs
Photographs as GIS layers
Historic Aerial Photos have been amassed by several government organizations such
as the United States Geologic Survey (USGS), the Department of Natural Resources
(DNR), the United States Department of Agriculture (USDA), as well as numerous private
These records are able to document the progress, growth, development, and change
of everything from meandering rivers to urban sprawl. By looking at a section
of land over time, the effects of urbanization, population growth, drought, erosion,
and others are more readily observed than in any other source of record. Several
industries count on these specific source of record for research including real
estate, development, mining, agriculture, geology, and many others.
Geographic Information Systems (GIS) have revolutionized the storage and ease of
access to these types of photographs. GIS is a way to store data geo-spatially;
that is, to reference data such as parcel boundaries, rivers & streams, contours,
even sewer lines to a point on the earth, and represent these in a dynamic three-dimensional
Formerly, these photographs were stored in large books and archived at federal,
state, and county offices as well as warehoused at private companies. Many
times particular groups did not include the entire city or county, and often these
were flown at different altitudes and at irregular intervals. This lack of
continuity is fertile ground for the spatial database structure of GIS.
The original film or in some cases its negative, are digitally scanned and stored
on disk. Consecutive years' photos are then manually orthorectified to ensure
they are overlaid accurately.
The photographs are next arranged into a mosaic to provide seamless alignment with
GIS stores these mosaics relationally in a database which allows access by association
with a parcel number, street address, or by some other type of data. The product
is viewable from your terminal at any time of day, and may be viewed, printed, or
pasted into a report on demand.
By combining several years' worth of data as separate layers in the same application,
property sites may be researched in less time with greater efficiency. The
result is a single online source that is more accessible to a user than having to
navigate the myriad of offices one would formerly need to visit.