Hii Ticker, reg. MDR16: When I print the encoded characters which require 8 or more bits in the order of the Huffman tree they build a sequence which appears at the end of MDR 16 (last 60 bytes or so). Those chars which are encoded with fewer bits are still a mistery to me. Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Gerd Petermann <gpetermann_muenchen@hotmail.com> Gesendet: Mittwoch, 15. Dezember 2021 13:07 An: Development list for mkgmap Betreff: Re: [mkgmap-dev] [mkgmap-svn] Commit r572: MDR16 is some kind of codebook. Hi Ticker, it's almost impossible to guess when there is only one entry in MDR 30/31 and only one occurence of the code "00000000000000000000". I used '#' in my debug code to mark an "unknown" char. A possible meaning could be that 30/31 are common prefixes and 32/33 are common suffixes in road names. I doubt that this is related to the Huffman encoding. Maybe the code "00000000000000000000" simply represents a special character that is replaced with a corresponding string in 30/31? No idea how that would work with the suffixes. Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Ticker Berkin <ticker@jagIT.co.uk> Gesendet: Mittwoch, 15. Dezember 2021 12:47 An: Development list for mkgmap Betreff: Re: [mkgmap-dev] [mkgmap-svn] Commit r572: MDR16 is some kind of codebook. Hi Gerd Do you think there might be some form of escape sequence that is followed by a ref to the clear road names in Mdr 30..33. I noticed when looking at MapInstall manipulated Mdr that the '#' sort got changed. Ticker On Wed, 2021-12-15 at 11:13 +0000, Gerd Petermann wrote:
Hi Ticker,
this is what I have so far. The non-printable characters 0x01..0x04 are probably not correct. Note the special case with the last sequence. It only occurs once in the index and may as well be an error in the data. My code doesn't detect any unknown codes, so I think MDR16 must somehow contain this information. The character ΕΎ seems to appear both in upper and lower case?!? Might be wrong.
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