Ontario Government Record Sub-Series RG 1-429-7
964,306 photographs : black and white prints
RG 1-429 Forest resource inventory records
Sub-series consists of aerial photographic prints created for forest resource inventory (FRI) by the Ministry of Natural Resources between 1946 and 1999.
These records consist of vertical aerial photography, where the photographs were taken directly overhead with the axis of the camera perpendicular or nearly vertical to the ground at the time of exposure.
Most of the photography is physically grouped by the FRI basemap numbering system. Basemaps (or dockets) are constructed from the latitude and lines of longitude. The FRI basemaps measure 7.5 minutes of latitude by 15 minutes of longitude (each degree is divided into 60 minutes; each minute is divided into 60 seconds). Each basemap is identified by a unique six-digit number that marks the latitude and longitude of the upper left-hand corner of the mapsheet or basemap. In each 1 degree by 1 degree quadrangle or box, there are 32 FRI basemaps arranged in 4 columns (60 minutes/15 minutes = 4) and 8 rows (60 minutes/7.5 minutes = 8). The coordinates of the upper left corner are expressed as degrees and 1/8 of a degree of latitude; and degrees and 1/4 of a degree longitude.
The scale for FRI photography is expressed in a pre-metric representative fraction. Photography for 1946 to 1987 is 1:15,840 (but excluding the 1952-1953 block in northeastern Ontario which is 1:31,680; and 1986 photography is 1:20,000). The scale of the photography for 1986, 1988 to 1997 is 1:20,000 (but excluding southern Ontario). The 1978, 1991 and 1997 southern Ontario photography scale is 1:10,000. Scales represent an average across any particular project and do not necessarily reflect the reality of any given photograph. Flight reports created for each negative roll contain the focal length of the camera lens and the flying height of the plane which may be used to calculate the true scale.
Photographs were taken with an endlap (the adjacent overlap of photographs along the same flight line) of approximately 60%. This enables one to view any features on the photographs stereoscopically, or in three dimensions. By viewing the given feature(s) from two different perspectives (i.e. using two adjacent "stereo" photographs) one can sense depth perception.
Photographs also have sidelap coverage (the adjacent overlap of photographs between parallel strips of coverage). It is approximately 10% and is required to ensure complete photographic coverage of an area as well as to provide control points for mapping. In using sidelap, it is possible to view the area duplicated on photographs between flight lines stereoscopically.
Complete ground coverage can be viewed by referring to every second photograph on a flight line. There is approximately 10% overlap between every second photograph on a given flight line.
Forest resource inventory aerial photographic prints are indexed by docket index maps which record the flight lines (or strips), negative roll and image numbers within a docket for one or more years, superimposed on topographical maps. Most photography has at least one related docket index map.
The majority of photographs are physically organized by docket number, year and then by flight line. However, a portion of the photographs in this sub-series are organized by flight line number.
Original negatives for the forest resource inventory photography can be found in sub-series RG 1-429-8 Forest resource inventory aerial photographic negatives.
Docket index maps for the forest resource inventory photography, which were originally filed directly with the photography in this sub-series, can be found in sub-series RG 1-429-10 Forest resource inventory aerial photography docket index maps.
The multi-part province-wide docket key index maps can be found in sub-series RG 1-429-9 Forest resource inventory aerial photograph docket key index maps.
Additional information concerning individual negative rolls can be found in sub-series RG 1-429-16 Forest resource inventory aerial photography flight reports.
Aerial photography and related records created by the Ministry of Natural Resources for provincial basemapping can be found in series RG 1-628 Ontario basemap records.
No further accruals are expected.
View an online list of these records.
Further information on navigating these records can be found in User Guide 232 : Finding Ministry of Natural Resources Aerial Photography.
Consult the Docket Index Key Maps (RG 1-429-9) to locate the docket number for the area of interest.
Consult the online list to identify the records that you require. The listing identifies the year of photography available for any given docket, status of prints, and location of related docket index map(s). Order using reference code and container number.
The docket index maps, which were originally filed with the photographic prints, have been separated to sub-series RG 1-429-10. The listing for RG 1-429-7 includes a reference to the container for the related docket index map.
Regional Index Maps (RG 1-429-11) may also be used to interpret the location of photography.
While effort has been made the capture the correct scale in the listing, users may wish to consult the flight report for the negative roll in RG 1-429-16 for verification.
Scroll up to "Finding Aid" for more information about any available finding aids or listings.