Download Compass Direction NEW!
Seiko Aytch
By the middle of the 18th century, the 32-point system had been further extended by using half- and quarter-points to give a total of 128 directions.[7]These fractional points are named by appending, for example .mw-parser-output .sfracwhite-space:nowrap.mw-parser-output .sfrac.tion,.mw-parser-output .sfrac .tiondisplay:inline-block;vertical-align:-0.5em;font-size:85%;text-align:center.mw-parser-output .sfrac .num,.mw-parser-output .sfrac .dendisplay:block;line-height:1em;margin:0 0.1em.mw-parser-output .sfrac .denborder-top:1px solid.mw-parser-output .sr-onlyborder:0;clip:rect(0,0,0,0);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px1/4east, 1/2east, or 3/4east to the name of one of the 32 points. Each of the 96 fractional points can be named in two ways, depending on which of the two adjoining whole points is used, for example, N3/4E is equivalent to NbE1/4N. Either form is easily understood, but alternative conventions as to correct usage developed in different countries and organisations. "It is the custom in the United States Navy to box from north and south toward east and west, with the exception that divisions adjacent to a cardinal or inter-cardinal point are always referred to that point."[8] The Royal Navy used the additional "rule that quarter points were never read from a point beginning and ending with the same letter."[9]
The table below shows how each of the 128 directions are named. The first two columns give the number of points and degrees clockwise from north. The third gives the equivalent bearing to the nearest degree from north or south towards east or west. The "CW" column gives the fractional-point bearings increasing in the clockwise direction and "CCW" counterclockwise. The final three columns show three common naming conventions: No "by" avoids the use of "by" with fractional points. Colour coding shows whether each of the three naming systems matches the "CW" or "CCW" column.
The traditional compass rose of eight winds (and its 16-wind and 32-wind derivatives) was invented by seafarers in the Mediterranean Sea during the Middle Ages (with no obvious connection to the twelve classical compass winds of the ancient Greeks and Romans). The traditional mariner's wind names were expressed in Italian, or more precisely, the Italianate Mediterranean lingua franca common among sailors in the 13th and 14th centuries, which was principally composed of Genoese (Ligurian), mixed with Venetian, Sicilian, Provençal, Catalan, Greek, and Arabic terms from around the Mediterranean basin.
This Italianate patois was used to designate the names of the principal winds on the compass rose found in mariners' compasses and portolan charts of the 14th and 15th centuries. The "traditional" names of the eight principal winds are:
Local spelling variations are far more numerous than listed, e.g. Tramutana, Gregale, Grecho, Sirocco, Xaloc, Lebeg, Libezo, Leveche, Mezzodi, Migjorn, Magistro, Mestre, etc. Traditional compass roses will typically have the initials T, G, L, S, O, L, P, and M on the main points. Portolan charts also colour-coded the compass winds: black for the eight principal winds, green for the eight half-winds, and red for the sixteen quarter-winds.
Navigation texts dating from the Yuan, Ming, and Qing dynasties in China use a 24-pointed compass with named directions. These are based on the twelve Earthly Branches, which also form the basis of the Chinese zodiac. When a single direction is specified, it may be prefaced by the character 單 (meaning single) or 丹.
Any ideas why there's a difference? Have I messed up on the rotation matrix stuff? I have the option of restricting the app to a single orientation, but it still concerns me that the compass reading still isn't very accurate (even though after filtering it's fairly stable)
Hmm. Well the last couple times I tested it I was walking from 1000m and 500m in a straight line heading north towards a node, with the arrow pointing to the top of the device (Which is supposed to be your direction of travel) and the north indicator was 180 degrees at the bottom.
Before I get to that, imagine being back standing on that imaginary piece of land at 0 degrees latitude and longitude standing in the direction mentioned above. Imagine also that you are blindfolded and your shoes are fixed to a playground roundabout. If someone shoves you in the back you will fall forward (toward North) and put both hands out to break your fall. Similarly if someone shoves you left shoulder you will fall over on your right hand. Your inner ear has "gravitational sensors" (youtube clip) which allow you to detect if you are falling forward/back, or falling left/right or falling down (or up!!). Therefore humans can detect alignment and rotation around the the same X and Z axes as the phone.
Now imagine someone now rotates you 90 degrees on the roundabout so that you are now facing East. You are being rotated around the Y axis. This axis is different because we can't detect it biologically. We know we are angled by a certain amount but we don't know the direction in relation to the planet's magnetic North pole.Instead we need to use a external tool... a magnetic compass. This allows us to ascertain which direction we are facing. The same is true with our phone.
The phone also has an electronic compass which behaves like a normal compass - its "virtual needle" points to magnetic north. Android merges the information from these two sensors so that whenever a SensorEvent of TYPE_ORIENTATION is generated the values[3] array has
values[0]: Azimuth - (the compass bearing east of magnetic north)
values[1]: Pitch, rotation around x-axis (is the phone leaning forward or back)
values[2]: Roll, rotation around y-axis (is the phone leaning over on its left or right side)
So I think (ie I don't know) the reason Android gives the azimuth (compass bearing) rather than the reading of the third accelerometer is that the compass bearing is just more useful. I'm not sure why they deprecated this type of sensor as now it seems you need to register a listener with the system for SensorEvents of type TYPE_MAGNETIC_FIELD. The event's value[] array needs to bepassed into SensorManger.getRotationMatrix(..) method to get a rotation matrix (see below) which is then passed into the SensorManager.getOrientation(..) method. Does anyone know why the Android team deprecated Sensor.TYPE_ORIENTATION? Is it an efficiency thing? That is what is implied in one of the comments to a similar question but you still need to register a different type of listener in the development/samples/Compass/src/com/example/android/compass/CompassActivity.java example.
I was having this issue so I mapped out what happens in different directions.If the device is mounted in landscape fashion, eg in a car mount the 'degrees' from the compass seem to run from 0-275 (going clockwise) above 269 ( between west and north) it counts backwards from -90 to 0, then forwards from 0 to 269. 270 becomes -90
We take measurements of our assets (poles) and use S123 very effectively. One of the field staff asked to see if using the device inbuild compass as a possible spirit level tool and read the values inside S123; ie need to calculate pole lean.
thank you @IsmaelChivite , this is great! Would it be possible to calculate the lean of the Pole in the current version? What i understand from your Bog it is the direction of the lean only, but not the magnitude.
i.e. now i am able to capture in which direction of the leaning pole ie 227deg, but not the actual pole lean i.e. 30deg. I would like to know the unit vector. S123 now had the ability of ϕ, but i was also looking at θ at an attribute. Hope this makes sense.
Felix,
I received today a brand-new CUAV V5 nano with the CUAV NEO GPS V2. Mounted the FC on a block of wood for all the calibrations. After compass calibration I see the same yaw 270 which is wrong.
FW= 4.0.3. as a Hexacopter.
I was reading the discussion between you and Holger and that is the reason why I am not fiddling further until this has been sorted. Btw all my upgrades on the other 3 aircraft into FW 4.0.3 was perfect. But not this new setup with the new FC.
After loading the Hexacopter FW 4.0.3 I connected the GPS, a radio and a small 3S battery on the timber board. I did first the full accelerometer calibration and than the compass calibration. Both finished with success. But the yaw changed from none to yaw 270. That is all I did. I repeated that a few times, the same result.
This FC should replace an older Pixhawk 1 in my Hexacopter. But not anymore.
All 3 aircraft got all the upgrade to FW 4.0.3 No new calibrations after upgrade. I also tested all 3 = 1 Heli, 1 quadcopter and my new Hexacoter. All 3 are flying normally in all modes I am using.
The new CUAN V5 nano is on the shelf now until I find an answer to that problem with the yaw 270.
Felix,
look at the bottom of the photo where the Heli is hovering. You can clearly see that the CUAV NEO V2 is mounted on the tail with the front arrow to 3 a clock and you see the green lights at 9 a clock.
The cable entry is confusing. Or even the opposite. Surely not front arrow to the front.
This should be in the manual that the magnetometer is fitted not in the flight direction, IMO, (but yaw270).
The latest V5 nano and V5+ flight control and NEO v2 GPS CUAV This flight control has been started with a traditional helicopter test flight, and will be supplemented with text and video later. [IMG_20190704_115238364] [YIAC0442] [IMG_20190704_121817850] [IMG_20190704_121157883] [YIAC0451] [IMG_20190704_122116413] [IMG_20190704_122051194] [IMG_20190706_102952762] [IMG_20190707_064719354] [IMG_20190707_064910518] [IMG_20190712_193112445_BURST005]
I checked by downloading the unprocessed image and the direction is indeed absent from the EXIF of the image. So I tried just taking a photo with the Open Camera app, and surprise : there is a direction stored in the EXIF, and it looked pretty good. So should I dump the Mapillary app altogether or is there an easy fix for that ?
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