Hi Steve

'The has_subtype bit is bit 23 of the LBL offset field and not the type
field. '

This is news to me - I'm following Mechalas who I must admit at times doesn't seem to be that reliable.

I have not as yet tried pois > &7f00 but have been looking at NT extended pois .
I have my suspicion that such pois have a limit of &16F or even lower
This is by examining extended pois with 8th bit of their subtypes set and by looking at the ' information stream' which follows a label if any.
I notice that mkgmap sets this bit for ,say, bus stops and adds eo 09 00 00 00
Looking at NT imgs I'm surmising that the length of this information stream is often extended if t(third?) and or fourth byte after the text null terminator has a value> &70
There are 2 bytes that precede any label, ie F1 31 but these cannot by them selves provide the length of the total poi block as I've come across pois with identical f1 31setc but different lengths.
Somehow if the fourth value <&70 ,( ?<&5F) it indicates the start of the next extended poi. My findings are not conclusive - you may know more.
So if extended pois have a limit below 1FF then perhaps pois have as well.

regards

Nick

On 23/09/2014 21:27, Steve Ratcliffe [via GIS] wrote:

Hi Nick

> Non extended POIs have their 8th bit set to denote the possible inclusion
> of a subtype.
> If so I make the maximum for a non extended POI to be &7F and not &FF as
> perhaps was implied?

The has_subtype bit is bit 23 of the LBL offset field and not the type
field.

Its always possible that the top bit of the type field is used for
something else or is just ignored. Have you tried such values and do
they work?

..Steve
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