# [R] Converting binary number to in Two´s complement representation

Richard M. Heiberger rmh @end|ng |rom temp|e@edu
Fri Jan 24 20:09:43 CET 2020

```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 <paulbernal07 using 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 (<rmh using 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 <paulbernal07 using 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:
>> >
>> >     ...1 ...2 ...3 ...4 ...5                         ...6 ...7       ...8
>> > ...9 ...10 ...11 ...12 ...13
>> > 1 !AIVDM    1    1   NA    A 15?f5H?P00rCQat5:Oah0?wn2 using S6 0*54 1485907200
>> > <NA>    NA    NA    NA  <NA>
>> > 2 !AIVDM    1    1   NA    A 1349B:3000rCtrn553aR using 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 using N9h00>TtPEQAslh03wuUwP06 0*29 1485907200
>> > <NA>    NA    NA    NA  <NA>
>> > 6 !AIVDM    1    1   NA    A 15A using 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 using S6,  1349B:3000rCtrn553aR using 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 using S6",
>> > "1349B:3000rCtrn553aR using JH02PRp", "D03Iuph1TNfp4dv9J<`N000",
>> > "D03Iu6QGLN01MdN01StN000",
>> > "B;s using N9h00>TtPEQAslh03wuUwP06", "15A using av3P00rClHn53<I8M?v02<2B",
>> > "1000Fo using P01rCuG<56bnkN?v004`0", "15QK900001JCq=d54l?5J0op0l4e",
>> > "15 using eD@8000rC`bl59kW`mFn004`0", "15QIK`0P00rC`Sb59jFUUgv02<1g",
>> > "403Iupiv4PU00rC9065>=fW00H0I", "403Iu6Qv4PU00rCk0d57rwW00<2g",
>> > "H5?AU:4U653hhhi8 using lkihP000000", "15TGcJ0002rD<>p55FgmI using Ul0H0S",
>> > "15Aq00?P00rC`a`59mFeogv004`0", "B;s using N9h00>TtPF1Asll03wP5wP06",
>> > "13P;K8 using Oh1rCfgp58=ec1bD22<4J", "139NL4000LrCc8j59FEED4 using 000S<",
>> > "403Iupiv4PU00rC9065>=fW00H0j", "39NS using m11@1rCrb:53:E<v0j3R000",
>> > "403Iu6Qv4PU01rCk0d57rwW00<2g", "15PvE using 0002rCi7R57pokCT:424`0",
>> > "15TgVb0000rCgVd57oFc31R42L46", "15PoOh0001rCgbt58CwUaBD004`0",
>> > "A03IupkAC4:dH0v90>@P1cF6nud using NrP5wH5T", "B;s using N9h00>TtPF1Asll03wPUwP06",
>> > "15E=q08P00JCrnR52cb>4?v200Sw", "7933.8836099999999",
>> > "15>uP00P00rC`U:59im;H?v22 using 1D",
>> > "54aMBf02:9M`?IDOH018DL4j085T000000000016>`Q8>4Oc0?@lRDm3hPC0",
>> > "3", NA, "1018lEWP?w<tSF0l4Q@>4?wp0W3h", "15BkV00P00rCQBf5:Q5JQOv42D1o",
>> > "35QN<D1000rCr5l53esbgPR20000", "B;s using 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 using G
>> > @W9K4Oi0D using PC0ShK40C",
>> > "PC using H8888880", "B;s using N9h00>TtPFQAslt03wQUwP06",
>> > "15De7F?P00JCr5r5517v4?v80h2P",
>> > "15U using cn0000rCgU>57oPLGiT:2D4D", "137g`F8007rCaIj59Tc5Dl using 800SN",
>> > "15?7P`0P00rD1S453KSlj?v824`0", "15?mqH?P00rCek458rkEN?v:00S4",
>> > "55R4:002?H<`Q3S7GR1<lUB0 using 4pF22222222220l000004p60;0E7kBE8888",
>> > "88888888880", "B;s using N9h00>TtPFQAslt03wR5wP06",
>> > "15E:BR0P00rCgaT58DdJUwv82H34",
>> > "15AIw`0P0GrCcO859DO5Ogv:0T`0", "14aMBf000wrCKKN5:sdU0Sv<083C",
>> > "1819?@H001rC9TB5=bppM9<82D0T", "13M using Hk00jSJD@RD4s=qG1mT80 using 3J",
>> > "15BI>P0001rCgUD58DRalRj:00S5", "100000?P00JCkt:583J=r?v:283Q",
>> > "A03IupkAC4:dH0N90C9p0goOwj<Cw`P05A7vnh081wqU05DFwAKw<0?va using 1>",
>> > "1gu00CLLwfh2 using Asw9@1<", "B;s using N9h00>TtPFQAsm003wRUwP06",
>> > "7933.8835099999997",
>> > "18K1kH000FrCSMt5:@;m>l8>0<4J", "19NSFKh000JCTeH5:7g1LT8:0`3g",
>> > "15E=m60000rC`W459k28Wnd:083h", "1:u0KOh001rCq5P529qqubqh2 using 3n",
>> > "13P>4mhw1CrCi5H57aK5WlN>0<4F", NA,
>> > "A03IupkAC4:dH0N90D=p0goP02<Cw``05A7vnwt81wqVwUDFwAOt<0?vah1>",
>> > "1gu103LLwfl1 using Asw9P1<", "14S8 using n001LrD?bH53iGe1rN>0 using 49",
>> > "B;s using N9h00>TtPG1Asm403wSUwP06",
>> >
>> > "15E:N using 0000rCgOd57p45bW><0<2H", "15 using EA<0P01JCo8l53=BFgwv using 0D47",
>> > "10007NgP00rCQGV5:Pa=?gv>2<1H", "15TILd?P00JCm4l53`D>4?v>0L1m",
>> > "19NSG<h003rCi@:57pmUkAB<0<1v", "B;s using N9h00>TtPG1Asm403wT5wP06",
>> > "15Q69 using 8000rCiDr57n`bp using tB2<4R", "15QtF00000rCafD59P?VJ9p<0H52",
>> > "15QCl@?P?w<tSF0l4Q@>4?wp0 using 5:", "15QDCP0P?w<tSF0l4Q@>4?wp0D1G",
>> > "803Iu6PF15REPH3 using Dh000000000002c88I2P0002IrbQ0@40TW`800000000",
>> > "HGp0772K07N4d1;0Pf71r0aj19RVmR19RVuR19RW5R19RW;t91Cjp31000C4",
>> > "15D8Gj0P00rCThP5:6T=2Ov>0 using 5H", "B;s using N9h00>TtPG1Asm803wTUwP06",
>> > "15ATk20000rCnrv53N6;gPr>085R",
>> > "55AP::02 using VAlQ3G;7:1<lUB0MD4 using DhuE0F22220l0`G465k90<PlRDm3hPC8",
>> >
>> > "88888888880", "15?lSL?P00JCQWD5:OpP0?vB24`0",
>> > "15BW=20P00JCrvH54t=an?vB00Sg",
>> > "13P;K8 using 001rCfgr58=f;QbFD2D4G", "A03IupkAC4:dH0v90FtP1cF6nud using NrP5wH5T",
>> > "85E:BR0F0P0000000000032jS2P000000DE7P3A00h0", "1349B:3000rCtrn553aR using JHD2d4O",
>> >
>> > "7933.8835099999997", "B;s using N9h00>TtPFQAsm803wU5wP06",
>> > "15B3Sj0000rC9RD5=mOh40jB20SU",
>> > "15TgVb0000rCgVb57oFc;ARF2 using 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)
>> >
>> > +   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 (<ruipbarradas using 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,
>> > >
>> > >
>> > > 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 (<ruipbarradas using sapo.pt
>> > > > <mailto:ruipbarradas using 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 using r-project.org <mailto:R-help using r-project.org> mailing list
>> > > >     -- To UNSUBSCRIBE and more, see
>> > > >      >> https://stat.ethz.ch/mailman/listinfo/r-help
>> > > >      >> http://www.R-project.org/posting-guide.html
>> > > >      >> and provide commented, minimal, self-contained, reproducible
>> > > code.
>> > > >      >>
>> > > >      >
>> > > >      > ______________________________________________
>> > > >      > R-help using r-project.org <mailto:R-help using r-project.org> mailing list
>> > > >     -- To UNSUBSCRIBE and more, see
>> > > >      > https://stat.ethz.ch/mailman/listinfo/r-help
>> > > >      > http://www.R-project.org/posting-guide.html
>> > > >      > and provide commented, minimal, self-contained, reproducible code.
>> > > >
>> > >
>> >
>> >         [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
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>> > https://stat.ethz.ch/mailman/listinfo/r-help