MBTiles Supported Options

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MBTiles Supported Options

Postby cornice » 2018-11-25 23:03

Hello,

Great job on Map Plus! It's by far the most feature rick iOS GIS app I have found.

I was recently testing QTiles for QGIS and MB-Utils. I generated three sample MBTiles files using tiles in these formats/schemes:

512px PNG TMS
256px JPG Slippy Map
256px PNG Slippy Map

Of these only the 256px PNG would render in Map Plus. Before I spend more time on this, would you please tell me what options should work in Map Plus in terms of MBTiles formats/options? To improve resolution, I would prefer to use 512px tiles but JPG compression would be helpful to reduce file size. I saw reference to an HD mode added to MOBAC which seems to indicate that 512px tiles should work. Maybe that is just with PNG and slippy map tiling scheme?

Thank you!
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Re: MBTiles Supported Options

Postby Zax » 2018-11-26 9:34

cornice wrote:Hello,

Great job on Map Plus! It's by far the most feature rick iOS GIS app I have found.

I was recently testing QTiles for QGIS and MB-Utils. I generated three sample MBTiles files using tiles in these formats/schemes:

512px PNG TMS
256px JPG Slippy Map
256px PNG Slippy Map

Of these only the 256px PNG would render in Map Plus. Before I spend more time on this, would you please tell me what options should work in Map Plus in terms of MBTiles formats/options? To improve resolution, I would prefer to use 512px tiles but JPG compression would be helpful to reduce file size. I saw reference to an HD mode added to MOBAC which seems to indicate that 512px tiles should work. Maybe that is just with PNG and slippy map tiling scheme?

Thank you!


There is no limitation on either tile format nor size, which means Map Plus supports load raster tiles of any size and image format from MBTiles, and Map Plus renders them by using the standard Google Map tile pyramid x-y-z index.
So there must be something wrong, maybe the plugin setting?

By the way, There is an easy way for a 256px tiled map to be resolution-improved in Map Plus. Please going to the imported mbtile map's Detail Information, and set its "Level Adjust" to "+1".

In order to improve resolution of a custom online map in Map Plus, such as Google, Bing, WMS, etc, the only thing we need to do is editing the URL pattern to request for a 512px image for the same x, y, z. For example, for Google maps, add "&scale=2" to the URL pattern, for WMS maps, set "&width=512&height=512".

Then, about MOBAC, our team (named as miocool years ago) have provided some source code to MOBAC for retina downloading supports years ago, I'm not sure if they are still active in the latest version. In so, there is no extra operation requires, but we only need to edit the URL pattern of a map source to fetch for a 512px tile, same like configuring the URL pattern in Map Plus for retina tiles above, then MBtiles created based on that URL pattern could be displayed in Map Plus with high resolution.
Zax Zeng
Duwei Technology
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