[mkgmap-dev] Is height: filter working as described?

Thu Feb 2 21:52:09 GMT 2017

Hi Andrzej

That is exactly right.

In particular I agree that it should be {ele|height:m} as it
has to have feet as the target unit.  Since the default unit in OSM
is meters even the :m part could be defaulted.

..Steve

> some guessing on my part, hope someone corrects if I'm wrong.
>
> As I understand, elevations in img are stored in feet.
>
> Filters hight:m=>ft and conv:m=>ft indicate, that value from source has
> to be converted into feet, as expected by img format.
>
> When you look at map, you see height units according to settings in GPS.
> You can set meters or feet. So for hight:m=>ft, these values are correct:
> ele=500, map: ", 500 m" = 1650ft, default conversion
> ele=500m, map: ", 500 m" = 1650ft, converted form meters
> ele=500ft, map: ", 152 m" = 499ft, preserved feet
>
> Settings in GPS are valid only for some objects types and label content.
> Conversion in GPS is done, when label starts with numeric or numeric is
> prefixed by special separator (it is [0x1f] for cgpsmapper). I guess
> filter "hight:" adds separator and GPS converts it to ", ".
>
> Now filter hight:ft=>m seems to be kind of useless. It converts feet to
> meters, stores this value in img and adds a prefix, indicating that
> value is in feet. What we need here, is no conversion but separator
> only. Maybe something like this could work: {ele|height:ft=>ft}.
>
> Actually it always should be feet as a destination for height, we could
> simplify this filter like this: {ele|height:m} or {ele|height:ft},
> indicating only default unit in source data.
>