now I am even more puzzled.
please complete the following two data.frames and send it to the list.
latDegrees lat2Comp
-90 xxxxxxxx
-89 xxxxxxxx
...
-1 xxxxxxxx
0 xxxxxxxx
1 xxxxxxxx
...
89 xxxxxxxx
90 xxxxxxxx
lonDegrees lon2Comp
-180 xxxxxxxx
-179 xxxxxxxx
...
-91 xxxxxxxx
-90 xxxxxxxx
-89 xxxxxxxx
...
-1 xxxxxxxx
0 xxxxxxxx
1 xxxxxxxx
...
89 xxxxxxxx
90 xxxxxxxx
91 xxxxxxxx
...
179 xxxxxxxx
180 xxxxxxxx
Your 8 bit 2C example has 7 digits of precision plus sign which gives
a range of (-127,127). That suffices for latitude (-90,90).
For longitude you will need 9 bits of twos complement for 8 bits of
precision plus sign to cover (-255,255), thus more than enough for
(-180,180).
This assumes that precision to the degree is sufficient. If you need
precision to minutes and seconds, or to meters, then you
will need even more bits in 2C.
Since it looks like you need a different number of bits for each
variable, I am asking for two data.frames.
Rich
On Fri, Jan 24, 2020 at 1:46 PM Paul Bernal <paulberna...@gmail.com> wrote:
>
> Hi Richard,
>
> That was just an example, to show that, for that particular string of binary
> numbers, the code works as expected. That is absolutely no related to the
> dataset I provided. If I try the function on the dataset, I get values well
> over the latitude and longitude boundaries (which should range from -90 to +
> 90, and -180 to +180).
>
> Regards,
>
> Paul
>
> El vie., 24 ene. 2020 a las 12:23, Richard M. Heiberger (<r...@temple.edu>)
> escribió:
>>
>> You show the example
>>
>> > fun("10110010")
>> [1] -78
>>
>> as satisfactory. Where in your posted data set do you find the input
>> string "10110010"?
>>
>> Please post a set of relevant input strings, and the answers you want from
>> them.
>> The rest of the columns are not helpful for this specific exercise.
>>
>> On Fri, Jan 24, 2020 at 11:34 AM Paul Bernal <paulberna...@gmail.com> wrote:
>> >
>> > Dear friend Rui,
>> >
>> > Hope you are doing great. Firstly, I want to thank you for your super
>> > valuable and kind support of always. As I mentioned in earlier e-mails, I
>> > am trying to decode AIS type messages, and the only ones I am having a real
>> > hard time with, is with latitude and longitude.
>> >
>> > I tried the function you provided me in one of your replies, and it works
>> > well with the examples you provided, but in other cases it doesn´t.
>> >
>> > The messages I am trying to decode are in the 6th column of the data. I
>> > will provide you with a small sample first, and then the complete dataset
>> > (which has 100 rows). This is the small sample:
>> >
>> > > head(dat)
>> > ...1 ...2 ...3 ...4 ...5 ...6 ...7 ...8
>> > ...9 ...10 ...11 ...12 ...13
>> > 1 !AIVDM 1 1 NA A 15?f5H?P00rCQat5:Oah0?wn2@S6 0*54 1485907200
>> > <NA> NA NA NA <NA>
>> > 2 !AIVDM 1 1 NA A 1349B:3000rCtrn553aR@JH02PRp 0*39 1485907200
>> > <NA> NA NA NA <NA>
>> > 3 !AIVDM 1 1 NA A D03Iuph1TNfp4dv9J<`N000 2*0D 1485907200
>> > <NA> NA NA NA <NA>
>> > 4 !AIVDM 1 1 NA A D03Iu6QGLN01MdN01StN000 2*43 1485907200
>> > <NA> NA NA NA <NA>
>> > 5 !AIVDO 1 1 NA <NA> B;s@N9h00>TtPEQAslh03wuUwP06 0*29 1485907200
>> > <NA> NA NA NA <NA>
>> > 6 !AIVDM 1 1 NA A 15A@av3P00rClHn53<I8M?v02<2B 0*2D 1485907200
>> > <NA> NA NA NA <NA>
>> >
>> > It is worth mentioning that each row of the 6th column provides several
>> > information about maritime vessels, like speed over ground, latitude,
>> > longitude, vessel ID, etc. I am only concerned with latitude and longitude
>> > since those are the only two fields I have not been able to decode
>> > successfully. Also, I am working on R version 3.6.2 for windows 64-bit OS.
>> >
>> > The messages to decode are of the following format:
>> > 15?f5H?P00rCQat5:Oah0?wn2@S6, 1349B:3000rCtrn553aR@JH02PRp, etc.
>> >
>> > Now, here is the complete dataset:
>> >
>> > > dput(dat)
>> > structure(list(...1 = c("!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM",
>> > "!AIVDO", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM",
>> > "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDO", "!AIVDM", "!AIVDM",
>> > "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM",
>> > "!AIVDO", "!AIVDM", "$GPRMC", "!AIVDM", "!AIVDM", "!AIVDM", "$GPGBS",
>> > "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDO", "!AIVDM", "!AIVDM", "!AIVDM",
>> > "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDO", "!AIVDM", "!AIVDM",
>> > "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDO", "!AIVDM",
>> > "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM",
>> > "!AIVDM", "!AIVDO", "$GPRMC", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM",
>> > "!AIVDM", "$GPGBS", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDO", "!AIVDM",
>> > "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDO", "!AIVDM", "!AIVDM",
>> > "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDO", "!AIVDM",
>> > "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM", "!AIVDM",
>> > "!AIVDM", "$GPRMC", "!AIVDO", "!AIVDM", "!AIVDM"), ...2 = c(1,
>> > 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
>> > 1, 1, 1, 1, 1, 50002, 1, 2, 2, 50002, 1, 1, 1, 1, 1, 1, 1, 1,
>> > 1, 2, 2, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2,
>> > 1, 50006, 1, 1, 1, 1, 1, 50006, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1,
>> > 1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 50010, 1,
>> > 1, 1), ...3 = c("1", "1", "1", "1", "1", "1", "1", "1", "1",
>> > "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1",
>> > "1", "1", "1", "1", "1", "A", "1", "1", "2", "1.3", "1", "1",
>> > "1", "1", "1", "1", "1", "1", "1", "1", "2", "1", "1", "1", "1",
>> > "1", "1", "1", "2", "1", "1", "1", "1", "1", "1", "1", "1", "1",
>> > "2", "1", "A", "1", "1", "1", "1", "1", "1.3999999999999999",
>> > "1", "2", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1",
>> > "1", "1", "2", "1", "1", "1", "1", "2", "1", "1", "1", "1", "1",
>> > "1", "A", "1", "1", "1"), ...4 = c(NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, 856.96783, NA, 7, 7, 1.5, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, 8, 8, NA, NA, NA, NA, NA, NA, 9, 9, NA, NA, NA,
>> > NA, NA, NA, NA, NA, 0, 0, NA, 856.96805, NA, NA, NA, NA, NA,
>> > 1.5, 1, 1, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 2,
>> > 2, NA, NA, NA, 3, 3, NA, NA, NA, NA, NA, NA, 856.96827, NA, NA,
>> > NA), ...5 = c("A", "A", "A", "A", NA, "A", "A", "B", "B", "A",
>> > "A", "A", "A", "B", "B", NA, "B", "A", "B", "A", "B", "B", "A",
>> > "B", "A", NA, "B", "N", "B", "A", "A", "3.2000000000000002",
>> > "B", "A", "A", NA, "A", "A", "A", "A", "B", "A", "A", NA, "B",
>> > "A", "A", "A", "A", "A", "A", NA, "A", "A", "A", "B", "B", "B",
>> > "B", "A", "A", NA, "N", "A", "A", "B", "B", "B", "3.2999999999999998",
>> > "B", "B", "B", NA, "B", "B", "A", "B", "B", NA, "B", "B", "A",
>> > "A", "B", "B", "A", NA, "B", "B", "B", "A", "A", "A", "A", "A",
>> > "B", "N", NA, "B", "B"), ...6 = c("15?f5H?P00rCQat5:Oah0?wn2@S6",
>> > "1349B:3000rCtrn553aR@JH02PRp", "D03Iuph1TNfp4dv9J<`N000",
>> > "D03Iu6QGLN01MdN01StN000",
>> > "B;s@N9h00>TtPEQAslh03wuUwP06", "15A@av3P00rClHn53<I8M?v02<2B",
>> > "1000Fo@P01rCuG<56bnkN?v004`0", "15QK900001JCq=d54l?5J0op0l4e",
>> > "15@eD@8000rC`bl59kW`mFn004`0", "15QIK`0P00rC`Sb59jFUUgv02<1g",
>> > "403Iupiv4PU00rC9065>=fW00H0I", "403Iu6Qv4PU00rCk0d57rwW00<2g",
>> > "H5?AU:4U653hhhi8@lkihP000000", "15TGcJ0002rD<>p55FgmI@Ul0H0S",
>> > "15Aq00?P00rC`a`59mFeogv004`0", "B;s@N9h00>TtPF1Asll03wP5wP06",
>> > "13P;K8@Oh1rCfgp58=ec1bD22<4J", "139NL4000LrCc8j59FEED4@000S<",
>> > "403Iupiv4PU00rC9065>=fW00H0j", "39NS@m11@1rCrb:53:E<v0j3R000",
>> > "403Iu6Qv4PU01rCk0d57rwW00<2g", "15PvE@0002rCi7R57pokCT:424`0",
>> > "15TgVb0000rCgVd57oFc31R42L46", "15PoOh0001rCgbt58CwUaBD004`0",
>> > "A03IupkAC4:dH0v90>@P1cF6nud@NrP5wH5T", "B;s@N9h00>TtPF1Asll03wPUwP06",
>> > "15E=q08P00JCrnR52cb>4?v200Sw", "7933.8836099999999",
>> > "15>uP00P00rC`U:59im;H?v22@1D",
>> > "54aMBf02:9M`?IDOH018DL4j085T000000000016>`Q8>4Oc0?@lRDm3hPC0",
>> > "3", NA, "1018lEWP?w<tSF0l4Q@>4?wp0W3h", "15BkV00P00rCQBf5:Q5JQOv42D1o",
>> > "35QN<D1000rCr5l53esbgPR20000", "B;s@N9h00>TtPF1Aslp03wQ5wP06",
>> > "34`odN1000rD1V2537=dfPJ60000", "15>nNj0000rCT<@5::qUpkt604`0",
>> > "15UHOn9P00rCQ`D5:OcTkgv80<4:", "35A=Rh1001rD;s454vSTuP`40000",
>> > "15U?B00000rCgb>58DFJfRl620RT", "55B7iD42CSGC<H`WF20L5>1=@5:222222222221@G
>> > @W9K4Oi0D@PC0ShK40C",
>> > "PC@H8888880", "B;s@N9h00>TtPFQAslt03wQUwP06",
>> > "15De7F?P00JCr5r5517v4?v80h2P",
>> > "15U@cn0000rCgU>57oPLGiT:2D4D", "137g`F8007rCaIj59Tc5Dl@800SN",
>> > "15?7P`0P00rD1S453KSlj?v824`0", "15?mqH?P00rCek458rkEN?v:00S4",
>> > "55R4:002?H<`Q3S7GR1<lUB0@4pF22222222220l000004p60;0E7kBE8888",
>> > "88888888880", "B;s@N9h00>TtPFQAslt03wR5wP06",
>> > "15E:BR0P00rCgaT58DdJUwv82H34",
>> > "15AIw`0P0GrCcO859DO5Ogv:0T`0", "14aMBf000wrCKKN5:sdU0Sv<083C",
>> > "1819?@H001rC9TB5=bppM9<82D0T", "13M@Hk00jSJD@RD4s=qG1mT80@3J",
>> > "15BI>P0001rCgUD58DRalRj:00S5", "100000?P00JCkt:583J=r?v:283Q",
>> > "A03IupkAC4:dH0N90C9p0goOwj<Cw`P05A7vnh081wqU05DFwAKw<0?va@1>",
>> > "1gu00CLLwfh2@Asw9@1<", "B;s@N9h00>TtPFQAsm003wRUwP06",
>> > "7933.8835099999997",
>> > "18K1kH000FrCSMt5:@;m>l8>0<4J", "19NSFKh000JCTeH5:7g1LT8:0`3g",
>> > "15E=m60000rC`W459k28Wnd:083h", "1:u0KOh001rCq5P529qqubqh2@3n",
>> > "13P>4mhw1CrCi5H57aK5WlN>0<4F", NA,
>> > "A03IupkAC4:dH0N90D=p0goP02<Cw``05A7vnwt81wqVwUDFwAOt<0?vah1>",
>> > "1gu103LLwfl1@Asw9P1<", "14S8@n001LrD?bH53iGe1rN>0@49",
>> > "B;s@N9h00>TtPG1Asm403wSUwP06",
>> >
>> > "15E:N@0000rCgOd57p45bW><0<2H", "15@EA<0P01JCo8l53=BFgwv@0D47",
>> > "10007NgP00rCQGV5:Pa=?gv>2<1H", "15TILd?P00JCm4l53`D>4?v>0L1m",
>> > "19NSG<h003rCi@:57pmUkAB<0<1v", "B;s@N9h00>TtPG1Asm403wT5wP06",
>> > "15Q69@8000rCiDr57n`bp@tB2<4R", "15QtF00000rCafD59P?VJ9p<0H52",
>> > "15QCl@?P?w<tSF0l4Q@>4?wp0@5:", "15QDCP0P?w<tSF0l4Q@>4?wp0D1G",
>> > "803Iu6PF15REPH3@Dh000000000002c88I2P0002IrbQ0@40TW`800000000",
>> > "HGp0772K07N4d1;0Pf71r0aj19RVmR19RVuR19RW5R19RW;t91Cjp31000C4",
>> > "15D8Gj0P00rCThP5:6T=2Ov>0@5H", "B;s@N9h00>TtPG1Asm803wTUwP06",
>> > "15ATk20000rCnrv53N6;gPr>085R",
>> > "55AP::02@VAlQ3G;7:1<lUB0MD4@DhuE0F22220l0`G465k90<PlRDm3hPC8",
>> >
>> > "88888888880", "15?lSL?P00JCQWD5:OpP0?vB24`0",
>> > "15BW=20P00JCrvH54t=an?vB00Sg",
>> > "13P;K8@001rCfgr58=f;QbFD2D4G", "A03IupkAC4:dH0v90FtP1cF6nud@NrP5wH5T",
>> > "85E:BR0F0P0000000000032jS2P000000DE7P3A00h0",
>> > "1349B:3000rCtrn553aR@JHD2d4O",
>> >
>> > "7933.8835099999997", "B;s@N9h00>TtPFQAsm803wU5wP06",
>> > "15B3Sj0000rC9RD5=mOh40jB20SU",
>> > "15TgVb0000rCgVb57oFc;ARF2@67"), ...7 = c("0*54", "0*39", "2*0D",
>> > "2*43", "0*29", "0*2D", "0*27", "0*1D", "0*26", "0*48", "0*4B",
>> > "0*3A", "0*34", "0*3A", "0*76", "0*0B", "0*4A", "0*72", "0*6B",
>> > "0*4E", "0*38", "0*04", "0*11", "0*17", "0*18", "0*6B", "0*64",
>> > "W", "0*53", "0*32", "2*20", NA, "0*61", "0*1C", "0*79", "0*16",
>> > "0*44", "0*53", "0*04", "0*2D", "0*1C", "0*07", "2*37", "0*12",
>> > "0*2D", "0*30", "0*6D", "0*25", "0*26", "0*75", "2*2D", "0*71",
>> > "0*38", "0*6D", "0*0F", "0*34", "0*1D", "0*70", "0*47", "0*70",
>> > "0*4C", "0*54", "W", "0*64", "0*66", "0*69", "0*0C", "0*70",
>> > NA, "0*11", "0*28", "0*38", "0*30", "0*1F", "0*64", "0*7C", "0*38",
>> > "0*67", "0*57", "0*59", "0*75", "0*52", "0*18", "0*08", "0*5F",
>> > "0*26", "0*3B", "0*67", "0*6A", "2*24", "0*47", "0*65", "0*56",
>> > "0*54", "2*76", "0*23", "W", "0*3B", "0*1D", "0*11"), ...8 = c(1485907200,
>> > 1485907200, 1485907200, 1485907200, 1485907200, 1485907200, 1485907200,
>> > 1485907200, 1485907200, 1485907200, 1485907200, 1485907200, 1485907200,
>> > 1485907201, 1485907201, 1485907201, 1485907201, 1485907201, 1485907201,
>> > 1485907201, 1485907201, 1485907201, 1485907201, 1485907201, 1485907201,
>> > 1485907201, 1485907201, 0.008, 1485907201, 1485907201, 1485907201,
>> > NA, 1485907203, 1485907203, 1485907203, 1485907203, 1485907203,
>> > 1485907203, 1485907203, 1485907204, 1485907204, 1485907204, 1485907204,
>> > 1485907204, 1485907204, 1485907204, 1485907204, 1485907204, 1485907204,
>> > 1485907204, 1485907205, 1485907205, 1485907205, 1485907205, 1485907205,
>> > 1485907205, 1485907205, 1485907206, 1485907206, 1485907206, 1485907206,
>> > 1485907206, 0.01, 1485907206, 1485907206, 1485907206, 1485907206,
>> > 1485907206, NA, 1485907206, 1485907206, 1485907206, 1485907206,
>> > 1485907206, 1485907206, 1485907206, 1485907208, 1485907208, 1485907208,
>> > 1485907208, 1485907208, 1485907209, 1485907209, 1485907209, 1485907209,
>> > 1485907209, 1485907209, 1485907209, 1485907209, 1485907209, 1485907209,
>> > 1485907209, 1485907209, 1485907209, 1485907209, 1485907209, 0.005,
>> > 1485907209, 1485907209, 1485907209), ...9 = c(NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, "*41", NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, "*43", NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA), ...10 = c(NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > 10217, NA, NA, NA, 1485907201, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, 10217, NA, NA, NA, NA, NA, 1485907206,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 10217, NA, NA, NA
>> > ), ...11 = c(NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA), ...12 = c(NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA),
>> > ...13 = c(NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > "D*6F", NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, "D*60", NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, "D*63", NA, NA,
>> > NA), ...14 = c(NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, 1485907201, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, 1485907206, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
>> > NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 1485907209,
>> > NA, NA, NA)), row.names = c(NA, -100L), class = "data.frame")
>> >
>> > To tested your function I took the first message, which is located in the
>> > 6th column and the 1st row, and did the following:
>> >
>> > library(stringi)
>> > library(dplyr)
>> > library(R.utils)
>> > library(RANN)
>> > library(NISTunits)
>> > library(pracma)
>> > library(celestial)
>> > library(stringr)
>> >
>> > dat <- readXL("U:/RawSampleData.xls", rownames=FALSE, header=FALSE, na="",
>> > + sheet="RawSampleData", stringsAsFactors=FALSE)
>> >
>> > testmessage1 <- dat[1,6]
>> >
>> > ascii_datformat <- utf8ToInt(testmessage1)
>> >
>> > Base <- ascii_datformat - 48
>> >
>> > decy <- ifelse(Base > 40, Base - 8, Base)
>> >
>> > biny <- intToBin(decy)
>> >
>> > binyframe <- data.frame(biny)
>> >
>> > tbinyframe <- paste(t(binyframe[,1]), collapse="") #at this point, I have
>> > the complete first message, all in binary format
>> >
>> > #according to the literature of AIS message decoding, longitude goes from
>> > position 62 to position 89
>> > #and latitude goes from position 90 to position 116
>> >
>> > longitude <- substr(tbinyframe, 62, 89)
>> > latitude <- substr(tbinyframe, 90, 116)
>> >
>> > #now I apply the function you provided me with:
>> >
>> > fun <- function(x){
>> > res <- sapply(x, function(y){
>> > if(nchar(y) %% 8 != 0 || substr(y, 1, 1) == "0"){
>> > strtoi(y, base = 2)
>> > }else{
>> > y <- unlist(strsplit(y, ""))
>> > -sum((y != "1")*2^((length(y) - 1):0)) - 1
>> > }
>> > })
>> > unname(res)
>> > }
>> >
>> > > fun(longitude)
>> > [1] 220663102
>> > >
>> > > fun(latitude)
>> > [1] 5414823
>> > >
>> > > fun("1101001001110000110100111110")
>> > [1] 220663102
>> > >
>> > > fun("000010100101001111110100111")
>> > [1] 5414823
>> > >
>> > > fun("10110010")
>> > [1] -78
>> >
>> > as you can see, the function only worked or showed expected result on the
>> > last case with a -78, but in the other cases, it the results were not as
>> > expected, maybe I am missing something here?
>> >
>> > Any help and/or guidance will be greatly appreciated,
>> >
>> > Best regards,
>> >
>> > Paul
>> >
>> > El lun., 20 ene. 2020 a las 10:28, Rui Barradas (<ruipbarra...@sapo.pt>)
>> > escribió:
>> >
>> > > Hello,
>> > >
>> > > The function I included converts signed binary numbers into their
>> > > decimal representation. They are negative if a) they are multiples of 8
>> > > bits and b) the most significant bit is a "1". If not just convert to
>> > > integer.
>> > >
>> > > As for a) above, I assume that you will have 8 bit numbers. And the
>> > > conversion is done as follows:
>> > >
>> > > input: 10110010
>> > >
>> > > splitting, to make it more clear:
>> > >
>> > > 1 0 1 1 0 0 1 0 - input
>> > > 0 1 0 0 1 1 0 1 - reversed
>> > > 1 - add 1 to the number with reversed bits
>> > > 0 1 0 0 1 1 1 0 - result is the two's complement
>> > >
>> > > c(0, 1, 0, 0, 1, 1, 1, 0) %*% 2^(7:0) is 78
>> > >
>> > > But the msb is "1" so it's -78
>> > >
>> > >
>> > > This is what the function does, but instead of %*% it uses
>> > >
>> > > sum(two's compl * powers of two)
>> > >
>> > >
>> > > Hope this helps,
>> > >
>> > > Rui Barradas
>> > >
>> > > The input must be a character string or character vector.
>> > >
>> > > Às 14:36 de 20/01/20, Paul Bernal escreveu:
>> > > > Dear friend Rui,
>> > > >
>> > > > Hope you are doing great, thanks for your kind feedback. The challenge
>> > > > I
>> > > > currently have at hand is to decode AIS messages and obtain latitude
>> > > > and
>> > > > longitude values from those.
>> > > >
>> > > > So basically, I want to accomplish something like in the example below.
>> > > > I want to convert this binary number (10110010) into the two´s
>> > > > complement representation, there is the logic they are using for that.
>> > > > Since longitude ranges from
>> > > >
>> > > >
>> > > > Example of conversion to decimal of a signed binary number in
>> > > > two's complement representation
>> > > >
>> > > > Let's convert to decimal the following signed binary number: 10110010
>> > > >
>> > > > 10110010 = -1×27 + 0×26 + 1×25 + 1×24 + 0×23 + 0×22 + 1×21 + 0×20 =
>> > > > -128
>> > > > + 32 + 16 + 2 = -78.
>> > > >
>> > > > El lun., 20 ene. 2020 a las 7:22, Rui Barradas (<ruipbarra...@sapo.pt
>> > > > <mailto:ruipbarra...@sapo.pt>>) escribió:
>> > > >
>> > > > Sorry, missunderstood the problem.
>> > > > Here it goes:
>> > > >
>> > > > fun <- function(x){
>> > > > res <- sapply(x, function(y){
>> > > > if(nchar(y) %% 8 != 0 || substr(y, 1, 1) == "0"){
>> > > > strtoi(y, base = 2)
>> > > > }else{
>> > > > y <- unlist(strsplit(y, ""))
>> > > > -sum((y != "1")*2^((length(y) - 1):0)) - 1
>> > > > }
>> > > > })
>> > > > unname(res)
>> > > > }
>> > > >
>> > > > fun("10110010")
>> > > > fun("10000000")
>> > > > fun(c("01000000", "01111111", "10110010", "10000000"))
>> > > >
>> > > >
>> > > > Hope this helps,
>> > > >
>> > > > Rui Barradas
>> > > >
>> > > > Às 11:38 de 20/01/20, Rui Barradas escreveu:
>> > > > > Hello,
>> > > > >
>> > > > > Is this what you want?
>> > > > >
>> > > > >
>> > > > > x <- "10110010"
>> > > > > strtoi(x, base = 2)
>> > > > > #[1] 178
>> > > > >
>> > > > >
>> > > > > Hope this helps,
>> > > > >
>> > > > > Rui Barradas
>> > > > >
>> > > > > Às 16:31 de 16/01/20, Paul Bernal escreveu:
>> > > > >> Dear friends,
>> > > > >>
>> > > > >> How can I convert the following binary number in two´s
>> > > > complement
>> > > > >> representation in R?
>> > > > >>
>> > > > >> 10110010
>> > > > >>
>> > > > >> Any help and/or guidance will be greatly appreciated,
>> > > > >>
>> > > > >> Best regards,
>> > > > >>
>> > > > >> Paul
>> > > > >>
>> > > > >> [[alternative HTML version deleted]]
>> > > > >>
>> > > > >> ______________________________________________
>> > > > >> R-help@r-project.org <mailto:R-help@r-project.org> mailing list
>> > > > -- To UNSUBSCRIBE and more, see
>> > > > >> https://stat.ethz.ch/mailman/listinfo/r-help
>> > > > >> PLEASE do read the posting guide
>> > > > >> http://www.R-project.org/posting-guide.html
>> > > > >> and provide commented, minimal, self-contained, reproducible
>> > > code.
>> > > > >>
>> > > > >
>> > > > > ______________________________________________
>> > > > > R-help@r-project.org <mailto:R-help@r-project.org> mailing list
>> > > > -- To UNSUBSCRIBE and more, see
>> > > > > https://stat.ethz.ch/mailman/listinfo/r-help
>> > > > > PLEASE do read the posting guide
>> > > > > http://www.R-project.org/posting-guide.html
>> > > > > and provide commented, minimal, self-contained, reproducible
>> > > > code.
>> > > >
>> > >
>> >
>> > [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> > https://stat.ethz.ch/mailman/listinfo/r-help
>> > PLEASE do read the posting guide
>> > http://www.R-project.org/posting-guide.html
>> > and provide commented, minimal, self-contained, reproducible code.
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