What is NT IMG format?
Many of the new features are a result of car sat nav development.
1) Routing is more compacted
2) Includes multiple lane routing/switching on a motorway
3) Handles Junction View (JCV), pictures that popup at junctions, stored as a SVG (text) file
3) polygons can have height to enable 3d structures
4) Searches include Post Codes
5) Can contain raster images(jpgs)
6) Better support for non english/american labelling
Exploring IMG Format
Discover how complex maps are created!
Find out ,step by step, how highways,polygons and pois are plotted in a Garmin IMG file and how names/labels are stored/unzipped..
Exploring IMG Format focuses on the RGN ,TRE LBL NET & NOD subfiles and includes various undocumented blocks in the RGN & TRE subfile using numerous examples to make its complicated structure more accessible.
It also explains how TOPO files are locked and what can still be retrieved.
Maplevels & Subdivisions
Maplevels are like zoom levels. Each map level contains a group of subdivisions. The last map level in an IMG file holds the most detailed subdivision(s) which unlike the earlier ones generally do not need to be left_shifted.
Offset 0 x 15 points to the first maplevel / subdivision as defined in TRE. with additional information in Exploring IMG Format
It generally starts with 2 byte offsets to a different element type , ie polylines or polygons,within a given map level block. If just one element, ie polylines, is found ,then the subdivision contains no offsets.
28 00 35 01 64 12 00 00 5e FF BD FF 17 64 CF 00 80 7A 00 94 FF 0F
Pointers are highlighed in bold:
More information in the following document:
Download Exploring IMG Format (pdf)
(latest with info on FID and PID & TRE SEP 3 2012)
|Advanced TYP Editor||Extract TYP from any IMG|