PTI Maps can obtain aerial photography at
altitudes that range from 200’ AMT to
20,000’ AMT for projects throughout the USA
and Caribbean.
Photography can be flown in black & white,
color, and infrared (black & white or false
color) depending on the final application.
Photography can be supplied as “hard copy”
or as digital images for softcopy data
reduction or large format digital printing.
Low-level photography (1’= 50’ scale, 300’
AMT) is flown with a helicopter at altitudes
ranging from 200’ AMT to 1,000’ AMT
providing photography at scales ranging from
1”=33’ to 1”=166’.
Conventional mapping photography is flown
using fixed wing survey aircraft at
altitudes that range from 1,000’ AMT to
20,000’ AMT providing photo-scales from
1”=166’ to 1’=3,333’.
The twin-engine survey aircraft (Piper or
Cessna) are equipped with either Zeiss or
Leica 6” focal length precision aerial
cameras that can incorporate Airborne GPS or
inertial measurement systems if required.
TOPOGRAPHIC & PLANIMETRIC
MAPPING
Topographic and planimetric vector mapping
is compiled at scales ranging from 1’=10’ to
1’=1,000’ with contour intervals from .5’ to
20’.
For topographic mapping the required
vertical accuracy of the final mapping
usually dictates the altitude at which the
photography is flown. (The lower the
altitude of the photography the higher the
vertical accuracy of the elevation data).
For planimetric mapping the size of the
features on the ground that have to be
compiled usually dictates the altitude of
the photography. (In urban areas features
such as manholes and water meter covers are
not identifiable on photography flown above
1,800’).
PTI Maps utilizes both analytical
instruments and softcopy workstations to
compile topographic and planimetric mapping.
All update mapping projects including
volumetric surveys are compiled using our
softcopy workstations, where the previous
map data can be displayed over the new
aerial photography. This improves the
identification of the areas that have
changed.
Digital map data can be supplied in AutoCAD,
Microstation, Terramodel or ARC/INFO formats
configured to any layer or level structure
requested by our clients.
ORTHOPHOTO MAPPING
Orthophoto mapping combines the positional
accuracy of a vector map with visual content
of a photograph. The fully rectified
photographic image can be used to accurately
scale distances or measure dimensions. The
digital Orthophoto provides an image
“backdrop” upon which any geo-referenced
data (property boundaries, wetland
boundaries, concept plans, internal lot
lines, existing utility information,
easements, planimetric features and
contours, etc.) can be displayed.
The Orthophoto is primarily a planning tool
and can be used for project development
meetings, public hearings and marketing. The
production of the Orthophoto image utilizes
the DTM data compiled for topographic
mapping and either the mapping photography
or photography (color, false color infrared
or black and white) flown specifically for
the final Orthophoto image.
PTI Maps produces digital Orthophoto mapping
from scanned images of black and white or
color aerial photography and DTM data
(usually compiled by photogrammetric
methods) using Cardinal Systems VrOrtho
software.
High-resolution black & white and color
digital Orthophoto imagery (up to .1 ft.
pixel), incorporating elevated structure
correction can be produced for specialized
applications,
Orthophoto mapping can be supplied as
“hard-copy” or as a digital image file for
display/use on most CAD and GIS systems.
Orthophoto mapping is a very cost effective
approach to County mapping programs, E-911,
Planning, Environmental Resource projects
and other Urban projects where there is a
significant amount of physical features to
be compiled (railroad yards, port
facilities, airports, etc.) the Orthophoto
is an excellent “backdrop” for land
development concept plans and exhibits for
public hearings.
As a digital product supplied in several
popular system formats, the Orthophoto
images can be incorporated into media
presentations and hard copy prints can be
produced inexpensively on most large format
printers.
ANALYTICAL TRIANGULATION
Analytical Triangulation is an industry
recognized standard procedure for densifying
photo-control on a photogrammetric mapping
project.
The procedure mathematically transposes
coordinates from the ground surveyed system
of control points established by the land
surveyor to supplemental control points
selected within the stereo models by the
photogrammetrist.
On projects with multiple stereo models and
larger projects with multiple lines of
photography Analytical Triangulation can
significantly reduce the amount of control
and targets that have to be established.
Analytical Triangulation also affords
greater flexibility in the placement of
control points on larger projects increasing
the efficiency of the surveying operations.
PTI Maps uses J. F. Kenefick software, Wild
BC 2 Analytical Instruments and a Wild PUG
IV point transfer device to complete
Analytical Triangulation projects.
HIGH ACCURACY VERTICAL
DATA
High Accuracy Vertical Data surveys are
compiled from very low altitude aerial
photography flown using a helicopter.
Vertical accuracies of .03’ on hard surfaces
are achievable utilizing aerial photography
flown at 300’ AMT.
HAVD surveys were originally developed to
increase the safety of survey crews when
collecting “edge of pavement” elevations for
Interstate widening design projects.
By supplementing photogrammetric data for
the traditional field survey EP data, survey
crews are not required to close traffic
lanes or work next to lanes of high-speed
vehicles.
HAVD has been utilized in producing existing
condition surveys of Interstate Highways,
Federal Facilities, large institutional
parking lots, existing roadway grading on an
urban renewal projects, bridge deck
replacement surveys, railroads and rock
faces.
An additional benefit of flying aerial
photography with a helicopter is the ability
to coordinate the photo-mission to the
minute with air traffic controllers and
police or security agencies. This is very
beneficial when obtaining aerial photography
on or adjacent to airports and in the
coordination with rolling roadblocks on
highway projects.
GIS SERVICES
GIS mapping capability and experience
includes both Cadastral mapping from deeds
as well as direct conversion of existing
maps. PTI Maps has extensive experience with
complex E-911 database construction,
including address attribution of structures
and road centerlines for direct linkage to
ANI/ALI data for dispatch of both landline
and Phase II wireless applications.
GIS services, to include complex ArcInfo
database designs and database development
for Utility feature conversion, Cadastral
mapping, E-911 Addressing and database
development, Planimetric mapping and Field
Survey/Inventory applications.
Data delivery formats include AutoCAD,
ArcInfo, ArcView, Microstation, and
Terramodel. PTI Maps
staff experience also
includes numerous related software formats
including ESRI packages of personal
Geodatabase and SDE, relational database
systems including ORACLE, MS Access, Dbase,
etc. and numerous specialty engineering
packages for volume, profile and earthwork
calculations.
