Tektronix H500 User Manual page 91

Operating basics
Map file concepts
The iMap tool uses two types of maps: Grid and Image.
Grid maps.
Grid maps have geophysical latitude and longitude coordinate references embedded in the map file. The instrument
uses grid maps, along with an active GPS receiver, to place measurements on a map at your current geophysical position.
Grid maps require specialized PC software to create or can be purchased from map-creating companies. The instrument can
load both GSF- and MIF-format grid map files. You need to convert non-GSF or MIF grid maps to GSF format before you can
load them into the iMap tool.
Grid maps require an active GPS receiver to correctly link measurements to geophysical map locations. An active GPS receiver
is a receiver that is locked to four or more satellite signals and is providing the instrument with accurate GPS location data. If
you load a grid map and a GPS receiver is either not connected or does not have a good satellite signal lock, the instrument
considers the grid map as an image map.
Image maps. Image maps do not have any geophysical latitude and longitude references embedded in the map file. An image
map is a graphical image, such as a scanned building floor plan or aerial photograph, to which you can attach measurements
at the point that you tap the screen.
Converting files to maps. The iMap Converter, a program that is downloadable from the Tektronix Web site, lets you convert
and save image files (BMP, JPEG, GIF, TIFF or PNG file) into GSF format image map files, convert image maps to grid maps, and
create grid maps from applications such as Microsoft MapPoint. (See page 80, The iMap converter program.)
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