Wanted: OBF file format description

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Wanted: OBF file format description

Bernhard R. Fischer
Dear list!

I'm looking for the .obf file format description?
Any suggestions?


Regards,
Bernhard

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Re: Wanted: OBF file format description

Imre Samu

2016-07-06 7:06 GMT+02:00 Bernhard R. Fischer <[hidden email]>:
Dear list!

I'm looking for the .obf file format description?
Any suggestions?


Regards,
Bernhard

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Re: Wanted: OBF file format description

Bernhard R. Fischer
On 2016-07-06 18:21, Imre Samu wrote:

>>  I'm looking for the .obf file format description
>
> maybe:
> - https://github.com/osmandapp/OsmAnd-resources/blob/master/protos/OBF.proto
> - https://groups.google.com/forum/#!searchin/osmand/obf$20protobuf
>
>
>
> 2016-07-06 7:06 GMT+02:00 Bernhard R. Fischer <[hidden email]>:
>
>> Dear list!
>>
>> I'm looking for the .obf file format description?
>> Any suggestions?
>>
>>
>> Regards,
>> Bernhard
>>



Thanks, your links give some hints about the format but it's still some
kind of mystery.

For a software implementation you need to know about every bit ;)


Regards,
Bernhard


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Re: Wanted: OBF file format description

Bernhard R. Fischer
On 2016-07-06 19:34, Gerd Petermann wrote:
> You need Googles protobuf compiler to convert it to e.g. c or java code.
>
> See https://developers.google.com/protocol-buffers/


According to this thread
(https://groups.google.com/forum/#!searchin/osmand/obf$20protobuf/osmand/0fmM_VtbH_A/GxlxfnpRCQAJ
) it is a container format and not plain protobuf. Probably it contains
protobuf files.

But still, even if it contains protobuf, that does not say anything
because protobuf is a generic format such us XML. Knowing that something
is XML does not explain the elements within the file ;)

Bernhard


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Re: Wanted: OBF file format description

Jesse Phillips
I haven't worked with this format, but I think this file does provide all the information needed to parse an OBF.

https://github.com/osmandapp/OsmAnd-resources/blob/master/protos/OBF.proto

The key here is that the OsmAndStructure message can't be parsed with a ProtocolBuffer implementation. Most of the fields are fixed at 32 bytes (to allow for random access). Check the comments to see which fields these are.

I don't know what the OsmAndTileBox is suppose to provide, but it has the comment "everything is encoded as 31 tile zoom" so that will need to be part of the utilization of that data.

Other than OsmAndstructure I think everything else is readable through standard ProtocolBuffers.

This information only really helps for parsing the information, manipulating it is a completely different mater and requires understanding how all the elements relate.

Good luck.

On Wed, Jul 6, 2016 at 11:27 AM Bernhard R. Fischer <[hidden email]> wrote:
But still, even if it contains protobuf, that does not say anything
because protobuf is a generic format such us XML. Knowing that something
is XML does not explain the elements within the file ;)

Bernhard

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Re: Wanted: OBF file format description

Bernhard R. Fischer
On 2016-07-07 03:13, Jesse Phillips wrote:

> I haven't worked with this format, but I think this file does provide all
> the information needed to parse an OBF.
>
> https://github.com/osmandapp/OsmAnd-resources/blob/master/protos/OBF.proto
>
> The key here is that the OsmAndStructure message can't be parsed with a
> ProtocolBuffer implementation. Most of the fields are fixed at 32 bytes (to
> allow for random access). Check the comments to see which fields these are.
>
> I don't know what the OsmAndTileBox is suppose to provide, but it has the
> comment "everything is encoded as 31 tile zoom" so that will need to be
> part of the utilization of that data.
>
> Other than OsmAndstructure I think everything else is readable through
> standard ProtocolBuffers.
>
> This information only really helps for parsing the information,
> manipulating it is a completely different mater and requires understanding
> how all the elements relate.
>
> Good luck.
>
> On Wed, Jul 6, 2016 at 11:27 AM Bernhard R. Fischer <[hidden email]>
> wrote:
>
>> But still, even if it contains protobuf, that does not say anything
>> because protobuf is a generic format such us XML. Knowing that something
>> is XML does not explain the elements within the file ;)
>>
>> Bernhard
>>
>


Thank you very much, that looks like a good starting point :)

Best regards,
Bernhard


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