treff: Re: [mkgmap-dev] DEM file and the block-size option
For overview-map it would be fine for me, but for detailed map I need a
block-size of 2k
Henning
On 13.01.2018 22:57, Gerd Petermann wrote:
> Hi all,
>
> I hesitate to commit this patch because I think that some users create
>
2018 15:21:18
> An: mkgmap-dev@lists.mkgmap.org.uk
> Betreff: Re: [mkgmap-dev] DEM file and the block-size option
>
> Hi Andrzej
>
>> - // There are 2 slots for the header itself.
>> + // There are 2 slots for the header itself. (slots or blocks?
>
Hi Gerd
@Steve: I see you are making progress in the auto-block branch. Please stop me
if this patch causes trouble
when merging.
It is not a problem for me.
It may be a while before the auto-block code is fully working and
tested, so the patch will be useful in the mean time.
..Steve
Hi,
I got once overview bigger than 32M and I had to decrease DEM
resolution. 64MB seems quite big for an overview.
Anyway, I have provided this patch, because I have finally found the
reason for big MDR sizes. I hope at least this one correction can be
moved to trunk.
--
Best regards,
And
Von: mkgmap-dev im Auftrag von Steve
Ratcliffe
Gesendet: Samstag, 13. Januar 2018 15:21:18
An: mkgmap-dev@lists.mkgmap.org.uk
Betreff: Re: [mkgmap-dev] DEM file and the block-size option
Hi Andrzej
> - // There are 2 slots for the header itself.
> + // There are 2 slot
Hi Andrzej
- // There are 2 slots for the header itself.
+ // There are 2 slots for the header itself. (slots or blocks?
code adds blocks)
int blocksRequired = 2 + headerSlotsRequired * 512 / blockSize;
It should be slots, the code is wrong. Also i
Hi,
here is attached temporary fix for block-size. List of changes:
* Default block size for img set to 1k. This allows for img up to 64MB.
User can change this value with option --block-size.
* Block size for overview map fixed at 1k. Not changeable by user.
* Block size for MDR fixed at 16k.
Hi Steve,
thanks, sounds great.
Gerd
Von: mkgmap-dev im Auftrag von Steve
Ratcliffe
Gesendet: Samstag, 6. Januar 2018 22:58:46
An: mkgmap-dev@lists.mkgmap.org.uk
Betreff: Re: [mkgmap-dev] DEM file and the block-size option
Hi Gerd
> not sure what
Hi Gerd,
> for MDR mkgmap sets the blocksize to 16384 if not set otherwise with
> the block-size option:
> params.setBlockSize(args.get("block-size", 16384));
I have seen this code. I think it is wrong to use the same option for
tiles and index. Index can be very big regardless of tile size.
Hi Gerd
not sure what to do here. I agree that 2048 looks like a good default, at least
for DEM tiles.
I am looking at this. I am going to remove all the existing code that
writes the FAT tables as that needs to the block size before you start.
The new code will calculate the best block
2018 20:39:12
An: mkgmap-dev@lists.mkgmap.org.uk
Betreff: Re: [mkgmap-dev] DEM file and the block-size option
Hi Gerd,
I have tested some img, changing block size with GMapTool. These are
results, first original file size, then size delta for blocks 1k, 2k and 4k:
14.8k -- +3.6k +9.9k +
Hi Gerd,
I have tested some img, changing block size with GMapTool. These are
results, first original file size, then size delta for blocks 1k, 2k and 4k:
14.8k -- +3.6k +9.9k +22.0k
109k -- +2.6k +7.7k +16.9k
1M-- +0.0k +5.2k +17.7k
2M-- -1.6k -0.5k +10.7k
3M-- -3.6k
Betreff: Re: [mkgmap-dev] DEM file and the block-size option
Hi Gerd,
> This disadvantage of a larger block-size is that your img files are
> typically a bit larger.
For small img yes. For bigger img larger block-size results in smaller
img size, since FAT contains less records and is smal
Hi Gerd,
> This disadvantage of a larger block-size is that your img files are
> typically a bit larger.
For small img yes. For bigger img larger block-size results in smaller
img size, since FAT contains less records and is smaller. I think you
simply could set block-size 2048 as default.
-
Hi Gerd
It would be a lot better and that is what happens for the gmapsupp file.
I should be able to make the code work for all IMG files.
Steve
>
>@Steve:
>If I got that right we should be able to calculate the optimal
>block-size
>as we do know the number of bytes that we will write to the i
Hi all,
the current default block-size is 512. This is used for most *.img files and
gives a maximum file size of 65534*512 ~ 32MB.
For large DEM files you might need a --block-size=1024 or even 2048.
If I got that right you may run into the next problem when using this option as
the mdr file wil
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