JCV File format

A junction view is a SVG file composed of multiple layers which may, or may not, be displayed. Layers have a type and ID.

There are 3 types of layers: signs, arrows, and backgrounds. A layer id is a number unique to layers of the same type in the SVG.

Most bytes of header &h61 are understood.

Pictures are in jpg , png or svg format and encrypted - see 0x37

The height and width of pictures follow the header.

	JCV Header &h61
00	Header Length	2
02	GARMIN JCV
oc	version?	2
0e	year	1
10	month	1
11	day	1
12	hour	1
13	minute	1
14	second	1
15	ID
21	Pointer to JCV1 containing ids	4
25	Length of record	2
27	length of block	4
2f	Pointer to JCV 2	4
33	Length of block	4
37	encryption bytes to decode picture blocks	4
3c	Pointer to JCV3	4
40	Length of block	4
44	Pointer to JCV4	4
48	Length of block	4
4c		2
50		2
52	Pointer to JCV4	4
56	Length of block	4
5a	?
62	base value for 0x64 - bytes for width & hight	2
64	multiples of 0x62 denoting number of picture sizes to follow	2
66	?
6c	width of pictures	4
70	height of pictures	4