SIX MAPPING TIPS
Here are some tips for capturing the best possible images for high-quality aerial maps.
AVOID FLYING OVER LARGE AREAS OF WATER. Water is
almost always in motion and is a highly reflective surface.
Large areas of water will not process well. If water must
be included in a survey area, the shoreline must remain
visible in the survey area to serve as a reference during
STAY AWAY FROM HIGHLY REFLEC TIVE SURFACES. An
area that is too bright reduces the detail needed to
reconstruct the scene. Wet pavement and the roofs
of large buildings are often too reflective to capture
properly. Mapping should be done at a different time of
day when sunlight is not reflected into the camera.
INCREASE OVERLAP FOR VEGE TATED AREAS. Trees are
hard to render because they are typically almost always
in motion and have a lot of fine detail. If there are a lot of
trees in the survey area, overlap should be set at 80 to
90 percent to make sure enough information is available
to represent the trees properly. Flying during calm winds
leads to better results.
CHECK THE EXPOSURE. White roofs of buildings and dark
wooded areas can become overexposed or underexposed.
They can appear as swirly areas on maps since not enough
data is available in those areas. Scouting the survey area
ahead of time, taking pictures, and examining test images
help determine the best exposure values.
FLY MUCH HIGHER THAN THE TALLEST STRUCTURE.
The taller the object, the less overlap it gets. The best
image quality for mapping is obtained from higher
altitudes. A tall object is viewed less often than an
object on the ground and will likely have problems
rendering. If the tallest object in the survey area is
10 meters high, the drone should fly at least 50 meters
above the ground. Images taken at low altitude have a
lower surface area per image and are difficult to stitch
together. Flying with minimal clearances not only is
dangerous but also produces maps with blocked areas
and generates poor results.
AVOID DARK SHADOWS. Mapping late in the day, when
the sun is low and the shadows are long, should be
avoided. If the exposure is set to compensate for bright
areas, shaded areas will lack sufficient detail. If the
exposure is adjusted for dark areas, light areas will be
blown out and will not have the required level of detail.
Shooting as close to the middle of the day fixes this
problem and has the added benefit of keeping exposure
times short and photo details sharp. K
MAPPING LATE IN THE DAY, WHEN THE
SUN IS LOW AND THE SHADOWS ARE
LONG, SHOULD BE AVOIDED. IF THE
EXPOSURE IS SET TO COMPENSATE FOR
BRIGHT AREAS, SHADED AREAS WILL
LACK SUFFICIENT DETAIL.