Thales Navigation Mobile Mapper - Manual (Page 92)

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Grid Mapper Utility
Introduction
Working with the Grid Mapper Utility is an easy way to log
GPS positions and GIS data at waypoints arranged in an
evenly spaced grid. This allows you to gather measurements
- made by field sensors such as depth sounders, chemical de-
tectors and magnetometers - in an organized fashion with an
easy-to-use navigation feature. You can then create contour
maps with the necessary density of data while avoiding any
gaps that might force you to return to the field.
Grid Features vs. Grid Points
The Grid Mapper Utility refers to two different grid con-
cepts: grid features and grid points.
- Grid features are arrays of uniformly spaced points ori-
ented in rows and columns.
- Grid points are navigation features similar to routes.
They are created by MobileMapper Office and uploaded
to the handheld. You navigate to each grid point using
MobileMapper and record your observations or measure-
ments using its data logging software.
Think of an apple orchard where the rows are about 15 feet
(5 meters) apart and each tree is about 15 feet (5 meters)
apart from the next tree in its row. The orchard is a grid fea-
ture. The location of each tree is a grid point. The number of
apples on each tree is the attribute you wish to record.
Like a point, line or area feature, a grid feature is a feature
geometry type. You can see the similarity in two ways:
- Just as a line or area feature is made of a string of point
positions, a grid feature is a set of points.
- As with line and area features, a single feature type name
corresponds to the entire grid feature. In a single job, you
might record positions and descriptions of several line
features classified as “roads” and two area features clas-
sified as “lakes.” And you might use one grid feature
named “water depth” and one named “magnetic field.”