BLM and land use... works, but no lakes?

[Luke]

Greetings all,

One feature that I had been missing from Osmand for a long time - and others in the US I'm sure would agree - is the ability to display the land use areas and what areas are national forest/BLM/etc.

I finally found a way to get it to download and show the public domain BLM maps! The steps are documented here: https://howtotrainyourrobot.com/adding-blm-land-use-maps-to-osmand-on-android/

This is handy but I noticed that lakes seem to not show when BLM map is the underlay. Perhaps a conflict, or a bug?

[Bart Eisenberg]

In the Underlay menu, is Show polygons on?

[Akkana Peck]

Bart Eisenberg writes:
> In the Underlay menu, is Show polygons on?

I just tried Luke's excellent tutorial. Thank you, Luke! It works
beautifully, and is a lot easier and more general than the QGIS method
I posted a few weeks ago.

And I tried Bart's tip for reservoirs, which worked (thanks to you
too!) but only after some fiddling. By default, the underlay map has
Base Map Transparency of 100%, and if I turn on Show Polygons, I see
the base (offline vector) map, including reservoirs, but the BLM
land use map disappears. But if I set Base Map Transparency to 50%
*and* turn on Show Polygons, I can see both reservoir and land use.
I can also see both if I use it as an Overlay (which I guess always
shows polygons? It doesn't have an option for that) rather than an
Underlay map -- though the first time I tried it as an Overlay it
didn't show and I'm not sure why.

Are there any arguments in favor of underlay vs. overlay, or are
they pretty much equivalent?

I don't suppose there's an option to download map tiles only when
on wi-fi? I couldn't find anything like that in the Online Maps
Settings, though there is a checkbox where I could temporarily turn
off updates.

...Akkana

[Luke]

I'm glad it works for you.

What is the QGIS method?

[Bart Eisenberg]

QGIS is an open source GIS program that can be used to georeference  maps and, with some manipulation, make them available as layers in OsmAnd.  

See Akkana Peck's discussion re: QGIS here, as well as in posts on this forum here. The program MAPC2MAPC also provides this capability under the Windows OS. My video on the topic is here.

Regarding using overlay vs. underlay: I think this is a matter of how you want to combine the two layers for a composite view.  In both cases, the slider determines the transparency of the upper layer.  If you use underlay, the upper layer is the OpenStreetMap vector map, and setting "Show polygons" on or off determines whether the raster map below shows polygon-like objects (like lakes) without the vector map interfering. Whereas with the overlay, the upper layer is a raster map, and no such selection is possible.  Hence in most cases, I think that the underlay map the more useful to start with.  

[Bart Eisenberg]

Here's the section of my video discussing the "Show polygons" option in the Underlay map menu: https://youtu.be/Y_fekLfcUOc?t=772