ThinkGeo.com    |     Documentation    |     Premium Support

MBTilesExtractor for .net core goes into infinite loop

#1

Hi,

Downloaded sample at https://github.com/ThinkGeo/MBTilesExtractorSample-ForWpf.NETCore, check “Extract Vector Tiles”, select a rectangle zone and add a name for generated map file, program goes into infinite loop.

Please take a look. Thanks,
Liang

MBTilesExtractorSample for WPF .net framework
#2

Hi Liang,

This sample looks cannot works well, our developer will update this sample after other tasks complete.

I will let you know if we upgrade a new version, please use the .net framework version for now.

Regards,

Ethan

#3

Hi Liang,

We updated this project today, could you please try it to see whether it works now?

Regards,

Ethan

#4

Hi Ethan,

It is working for me. Thank you.

I have a few comments though.

  • Mapfile extracting is much slower than .NET framework version. For example of Wyoming, .NET framework takes less than 2 minutes, while .NET core takes 20 minutes. Maxzoom level is set to 20 for both cases. Generated map files size is around 80MB.

Thanks,

Liang

#5

Hi Liang,

Thanks for your feedback, our developer will test it and see whether anything we can do on the performance.

Because version 12 is different to previous version, so it’s not the same in many features, but we will keep enhance the new version, please keep your eyes on our product.

Regards,

Ethan

#6

Hi Ethan,

A few more questions from our testing:

  1. Per the specifications, the database MUST contain a table named tiles. The extractor only produces a VIEW – NOT a table. See attached picture Database_Structure.png.
    Not sure if this a huge problem, but it does not allow for an INDEX to be created for tiles. Curious if an index would increase the speed to load the tiles.

  2. Also, we tried to use another program- Maptiler to open the MBTILE files created from the extraction. We got the following error: “MBTiles file is malformed: missing bounds value in metadata.” See attached picture ErrorMessage.png.

Thanks,
Liang

Database_Structure
Database_Structure861×547 39.2 KB
ErrorMessage

This metadata is supposed to be in the MBTILE file.

#7

Hi Liang,

Thank you very much of raising this up. The existing version of *.mbtiles doesn’t follow the specification of vector tile defined at https://github.com/mapbox/mbtiles-spec/blob/master/1.3/spec.md, but generated with the “Docker” from “OpenMapTiles” after some changes. That’s the reason why it gives some problems to you. Here below are the comments of the questions:

#1. The View “Tiles” is created with tables “images” and “map”, the index is created on these 2 tables to speed up the performance. In that case, we don’t need to create index for view, so not a huge problem, don’t worry about it.

#2. It’s proved to be a bug in the utility “MBTilesExtractor for .net core”, it’s has been fixed in the latest push, please pull the update to take a try. Sorry for the problem.

Besides, I was excited to let you know a complete new version of “World Streets MbTiles” will be available pretty soon (maybe one week after), following the specification 1.3. Besides “OpenStreetMap”, “Natural Earth”, more data from ThinkGeo and “OpenAddresses are integrated”, it’s well organized and has an eye-catching style. If you are interested in, please contact support@thinkgeo.com or we will update it here when it’s available.

Thanks,

Johnny

#8

Hi,

I downloaded the new map from link provided by Clint. The MBTilesExtractor for .net core at https://github.com/ThinkGeo/MBTilesExtractorSample-ForWpf.NETCore/commits/master does not seem to work with the new file. It generated a 68KB file then got stuck. Two example outputs are attached. Also, the new file does not seem to show state names.

Please take a look. Thanks.ExtractorOutput.zip (2.5 KB)

Liang

#9

Hi Liang,

This issue has all been taken care of in our meeting yesterday. I will publish the new MBTilesExtractor after it’s polished. Just let me know when you have any more questions.

Thanks,
Ben