mbtiles as layers

[Radagast]

Is it possible to show multiple mbtile files as layers in the same way as you can do the sqlite layers?

  Is geopapa limited to only showing 1 mbtiles file as a basemap?  

If this is a limitation, what would need to be done to add this functionality. 

 It would be great if you could display mbtiles as layers like you can with the sqlite.

[andrea antonello]

> Is it possible to show multiple mbtile files as layers in the same way as
> you can do the sqlite layers?

no

> Is geopapa limited to only showing 1 mbtiles file as a basemap?

yes

> If this is a limitation, what would need to be done to add this
> functionality.

That would be rather hard to do I think. Also it is not something at
geopaparazzi level, but at the underlying mapsforge level. You will
need to work on that library and interact with their community.

Andrea

>
> It would be great if you could display mbtiles as layers like you can with
> the sqlite.
>

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[Mark Johnson]

Is it possible to show multiple mbtile files as layers in the same way as you can do the sqlite layers?

I assume here that you are talking about Image-Layers:

- base layer

- second Image with a transparency setting so that the base layer can be seen underneath

  Is geopapa limited to only showing 1 mbtiles file as a basemap?

The term 'baselayer' comes from the mbtiles Specfication and is the default value of the metadata-parameter 'type'.

- there is, to my knowledge, no other value for 'type' has ever been used - nor implemented.

-- I assume that it was the (long term) intention to support layers with this parameter

Geopaparazzi is limited, as far as the map rendering goes,  by what the mapsforge project offers.

- we use the last known version that support local tiles.

- Mapsforge present development seems to concentrate now on online services only

- there is only a single layer support given from the Mapsforge Library

 

If this is a limitation, what would need to be done to add this functionality. 

Multiple-Layer support would have to be build in

- Wms-Servers have build in Multiple-Layer support:

-- they combine the different Images (one for each layer) into 1 Image on the Server and returns this

-- this (single) Image is then received by map-render’s like mapsforge and shown

The only practical way (i.e. NOT changing the present Mapsforge Library - something that should be avoided) of doing something like this, would be through the further use of the Mapsforge Overlay logic.

This could be a 'ImageLayerOverlay.java' based on the 'Overlay' class

- it could contain the reading of the images of everything BUT the 'baselayer', using any transparency settings

- create the final image that then would be 'painted' over the 'baselayer'

- after-which the present 'GeopaparazziOverlay.java' would run (where the notes,gps and geometries are 'painted')

This COULD be a practical solution for this, depending on what the Image manipulation classes offer

- blending, transparency, combing multiple Image to one - but also resizing:

--  resize the 256x256 tile to a 512x512 tile so that on high resolution machines they become readable

 It would be great if you could display mbtiles as layers like you can with the sqlite.

Yes it would.

But this is also a question of Human resources, since there are two of us working on this project.

Mark Johnson, Berlin Germany

[Radagast]

mbtiles is in essence an sqlite db right ?

[Eli Adam]

On Mon, Mar 10, 2014 at 6:44 AM, Radagast <promptn...@gmail.com> wrote:
> mbtiles is in essence an sqlite db right ?

Yes, but you can put a lot of data in sqlite. In the case of mbtiles,
raster data and thus nothing like a sqlite db with vector data.

Eli