Digital
Mapping
Is there any
digital mapping available for the province? If so, what are the
coverages? top
Yes, there is digital mapping
available at the following scales:
- there is complete coverage for
Newfoundland & Labrador at 1:250,000 scale;
- there is complete coverage of
the island of Newfoundland at 1:50,000 scale and
approximately 75 % of Labrador is available;
- we have many of the
communities of Newfoundland and Labrador available at 1:5000
and 1:2500 scale
Do the digital
files use the same datum as the paper maps?
top
No. All of our digital maps use
NAD83, while many of the paper maps are still based on NAD27. As
our division creates new community mapping the paper maps are
produced in NAD83. Also, whenever we do revision mapping in a
community, the old NAD27 maps are disgarded and replaced with
the new NAD83 maps.
Are all of our
digital maps structured?
top
No. All of our resource maps
(i.e. 1:250,000 & 1:50,000) are fully structured. All new
community mapping (i.e. 1:5,000 & 1:2,500) are fully
structured, however, we do have approximately 1900 community
maps that are scanned & vectorized, but are not structured.
All of the data contained in these files are on the same theme
and have the same feature code.
Is there an index
available which shows all available digital mapping for the
province? top
No
Is there any meta
data available on our Digital topographic maps?
top
Yes, there is. Click here.
Map
Projections
What is the
difference between the 6º UTM (Universal Transverse Mercator)
& the 3º MTM (Modified Transverse Mercator) projection?
top
Click UTM
Zones for a diagram showing the central meridians, zone
widths and projection parameters.
Click MTM
Zones for a diagram showing the central meridians, zone
widths and projection parameters.
Geodetic
Surveys
What does
Geodetic Survey mean?
top
Geodetic Surveys is essentially
the precise measurement of the earth. Today global positioning
technology is the main tool used to accomplish this task. The
physical part of this is a network of control survey markers
which have been installed and surveyed throughout the province.
What are the
approximate northing & easting shifts from NAD27 to NAD83
for the province? top
There are considerable
differences in both the latitude and longitude coordinates and
the northing and easting values. These shifts vary considerably
with location, and there is no constant shift which can be
applied for all areas. The following tables gives an indication
of the magnitude of shifts for three areas of the province.
| Geographic
Coordinate Shifts from NAD27 to NAD83 |
| |
Port aux
Basque |
St. John's |
Goose Bay |
| Latitude in
Seconds |
0.03 |
0.20 |
0.27 |
| Longitude in
Seconds |
2.33 |
3.52 |
3.18 |
| MTM
Coordinate Shifts from NAD27 to NAD83 |
| |
Port aux
Basque |
St. John's |
Goose Bay |
| Northing in
metres |
219 |
213 |
226 |
| Easting in
metres |
55 |
73 |
56 |
Where can I find
information on the control survey network for the province?
top
Information on the provincial
control survey network maybe obtained by contacting:
Are there any
programs available that will allow you to transform coordinates
between NAD27 & NAD83 or to convert latitude and longitude
to MTM and UTM projections and vise-versa?
top
Yes. The National Transformation
Program can transform coordinates from NAD27 to NAD83, while
GSRUG can convert between latitude and longitude and MTM or UTM.
The National Transformation Program can be obtained from the
province by calling (709) 729-3305 and GSRUG, which was
developed by the federal government, can be obtained by calling
613-995-4410..
Do we have any
software programs that will calculate magnetic declinations?
top
Yes, we do have software that
will calculate magnetic declinations. However, we usually refer
people to the federal government website called the Canadian
National Geomagnetism Program. This site allows individuals
to calculate the declinations online.
How is the
control survey information compiled and what are the associated
costs? top
All of the control survey
information for the province has been compiled on a CD. This
includes 6100 control survey markers sketches, 165 index maps
and software to view, retrieve and print the information. The
cost for this CD is $200.00 plus HST.
What datum is
being used in the province?
top
The North American Datum of 1983
(NAD83) was adopted on January 1,1993. Prior to that NAD27 was
used.
Aerial
Photography
Where can I buy
Air Photo's of Newfoundland?
top
Air Photo and Map Library
Department of Government Service and Lands
Howley Building, Higgins Line
ST. JOHN'S, NL. A1B 4J6
Telephone: (709) 729-3305
Facsimile: (709) 729-6136
Where can I find
an old aerial photograph of Grand Falls?
top
Aerial photographs have become
common place and are used by resource planners, land-use
experts, environmentalists, engineers, scientists, and a wide
variety of other users. But many people want a historical aerial
photograph for many reasons. To locate the boundaries of their
land or to give as a gift. To show change in their area.
The Air Photo and Map Library has
coverage of the island and mainland portion of the province
dating back to the 1940's. Check with them to see if they have
your area. Some of the more productive areas of the province are
flown every ten years.
What is the scale
of this photography?
top
A photographic scale just states
that one unit of distance on a photograph is a representation if
a specific number of units of actual ground distance. Often
expressed in three ways. Unit equivalent, representative
fraction or a ratio. For example a photographic scale of one
millimeter on the photograph would be 12.5 metres on the ground
and would be expressed as: a ratio of 1:12,500, representative
fraction 1/12,500 or unit equivalent of 1mm =12.5 m.
Another two terms often confused
when discussing scale is large and small scale photos. Large
scale photo means that the ground features are larger giving
more detailed size but the ground coverage that is seen on the
photo is less than in at smaller scale. Small scale photo means
that the ground feature are smaller and less detailed. The
ground coverage on the photo is greater than the larger scales.
The Air Photo and Map Library has a variety of photographic
scale available.
How big can I get
the air photo enlarged to?
top
Due to the limits of our
equipment we can only enlarge the full negative up to 3x or 71cm
x 71cm, (28" x 28"). We can enlarge a portion of
aerial photograph up to 3x or more depending on the quality of
the original negative but due to loss in resolution we have
found that 5X gives the best result. The biggest print we can
make is 71cm x 102cm ( 28" x 40").
What are Air
Photo Mosaics and do you make them?
top
A photo mosaic is a series of
aerial photographs that are put together so that the detail of
one photograph matches the detail of all the adjacent
photographs. There are three main types: controlled, semi
controlled and uncontrolled mosaics. Controlled mosaics have the
prints tone- matched and rectified to fit a base map and each
print must have at least three ground control. The
semi-controlled Mosaic has tone matched print but are not
rectified and are fitted to a map base of the same scale.
Uncontrolled mosaics are prints that are joined together to get
the "best fit". They can be tone-matched.
Due to a lack of demand for this
service we no longer offer Air Photo Mosaics but can supply you
with tone-matched unrectified photos so you can do your own
uncontrolled mosaics.
Do you have
Digital Aerial Photography for sale?
top
Due to a demand by geomatics
professionals we are looking into getting our aerial photographs
digitalized but we are not able to offer this service yet. We
are still looking into standards and what formats would be best
for the customers. We know that digital aerial photographs are
becoming available as Tagged Information File Format (TIFF) at
resolutions of 600 dpi which means that a B∓W aerial
photograph would be approximately 30MB in size while the colour
photograph would be 90MB. If you have any suggestions let
us know.
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