How to "thin out" data to shrink map size?

Hi everyone,

i’m making my own maps since a while now and have reached a limit with the map size. I want to use a 2GB memory card in my etrex Vista HCx, because the units operation slows down dramatically when using a 8GB card. :frowning:

Since the data size in OSM is constantly increasing, i want to reduce the size of my generated map to conserve memory. I want to drop data, for example planned motorways, which are rendered on the unit but useless for my needs.
My internet recherche leads to two possibilities:

  1. Filtering the data with osmfilter.exe.

  2. Changing my mkgmap-style-file to drop specific tags.

For the first alternative i need the tags for planned roads, which i could possibly drop - but i have no idea what these tags are? :expressionless:

For the second alternative i could not find a way to drop specific tags inside a style-file, but maybe i’m blind? :confused:

Or is there probably another, maybe even better way to do this?
Any help appreciated!

Kind regards, Uli

I’m using both methods.
With 1) I’m filtering buildings and with 2) I filter all tags I don’t need.
The advantage of filtering in stage 1) is, that the splitter is generating less and larger tiles.

concerning your questions:
Tag for planned roads is highway=proposed, you can probably also remove highway=construction
To drop a tag in the style file you simply delete the corresponding rule or you can use the --delete-tags-file option
of mkgmap.


Hi Chris,

thank you very much, that helped a lot! :slight_smile:

Have you ever thought of

  1. Rendering smaller areas on-demand?

For walking tours I plan the tour with BaseCamp, and make a rough bbox around the area I vist. Then I cut the osm.pbf to that area, having only one tile for OSM data and one tile for SRTM.
The map making process is rapidly fast, and the etrex shows the map quickly.

Moving only the tiles around my trip as offered by BaseCamp is almost the same in most cases.



Where can I find this OSMFILTER.EXE? I’m also interested in filtering before generating tiles.
Update: sorry found it already

gr Wim