Spectra Precision MobileMapper Field & Office Software - Manual (Page 34)

English
26
reception status. Then you can start collecting your first
feature.
Logging a Point
Feature
• Stand near the point you want to log.
• Tap Log (or press the “–” key underneath). A menu
appears listing all the layers in the job.
• Tap on the point layer name (“Points” in our example).
• Tap on the Settings tab and check or change the averaging
time expressed in seconds. As the last chosen averaging
time is prompted by default, you may not have to view this
tab every time you log a new point feature.
• To log the point with an offset, tap on the Offset tab and
enter the following parameters (for no offset, just check
that the horizontal distance and vertical offset are 0 on
this tab and proceed to the next step):
–
Bearing: This field is filled automatically either from
the GPS compass, the E-compass if this option is
activated in
Menu> Options> E-compass, at the time you
access the Offset tab, or from the range finder, if there
is one (see below).
If the E-compass is used, a valid measurement will be
made if you take care to hold the receiver horizontally
in the direction of the point feature, before you start
logging the feature.
If neither the E-compass nor a range finder is used,
then the GPS compass can provide this value by
default. A valid measurement will be made if you take
care to steadily walk in the direction of the point
feature before you start logging the feature.
– Horizontal Distance field: Distance to the point feature.
If a range finder is used, tap on the
Read Range Finder
button once the range finder can provide valid
measurements. This action will automatically fill in the
Bearing and Horizontal Distance fields.
If no range finder is used, type an estimate of the
horizontal distance directly in the field using the
keyboard. The better you estimate the distance, the
better the collected position.
– Vertical offset field: Height deviation from the physical
location of the feature to the ground, positive if above
the ground, negative otherwise (see illustration).
Bearing
d= Horizontal Distance
d
N
Coord S
ys
Ground
HA
HF
HG
VO
HF = HG - HA + VO
Where:
HF: Feature height expressed
on coordinate system used (computed)
HG: GNSS height (measured)
HA: Antenna Height above ground
(user set)
VO: Feature height above ground
(vertical offset, user-set)