sensoff
Corrects field transect coordinates when an on-the-go sensor is offset from the GPS on a mobile survey platform.
$ python -m sensoff --ioff -0.5 --loff -1.5 --skiprows 1 sensor_survey_GAMMA.csv
Determining the position of an offset on-the-go sensor is relatively straightforward if the heading of the mobile platform at each GPS reading is known. The problem is that the heading is not known: the platform's position is recorded by the GPS, but not its direction. To calculate the sensor location, the unknown heading at each point is estimated to be a weighted average of the bearings of the prior and subsequent legs of the traverse.
See:
Scudiero, E., D. L. Corwin, P. T. Markley, A. Pourreza, T. Rounsaville, and T. H. Skaggs. 2020. A novel platform for on-the-go sensing in micro-irrigated orchards. Computers and Electronics in Agriculture. In Preparation.
Install
$ pip install sensoff
Examples
From the command line:
$ python -m sensoff --help
usage: sensoff [-h] [--ioff IOFF] [--loff LOFF] [--xcol XCOL] [--ycol YCOL] [--skiprows SKIPROWS] [--sep SEP] [--outfile OUTFILE] FILE
Correct transect coordinates when sensor is offset from GPS
positional arguments:
FILE Delimited text file with GPS x,y coordinates
optional arguments:
-h, --help show this help message and exit
--ioff IOFF inline sensor offset, positive in direction of travel
(default: 0)
--loff LOFF lateral sensor offset, positive to left (facing
forward) (default: 0)
--xcol XCOL x-coordinate column (1-based) (default: 1)
--ycol YCOL y-coordinate column (1-based) (default: 2)
--skiprows SKIPROWS number of datafile header rows to skip (default: 0)
--sep SEP datafile delimiter (default: ",")
--outfile OUTFILE write output to file
lateral_offset
(+)
| Direction of travel -->
>>>>>>>>>>>>>
> | >
(-) --->--- GPS --->--- (+) inline_offset
> | >
>>>>>>>>>>>>>
|
(mobile platform)
(-)
On the platform, sensor is 1.1 m behind and 0.5 m to the left of the GPS
$ python -m sensoff --ioff -1.1 --loff 0.5 datafile1.csv
The first row of datafile2 is a header row that should be ignored
$ python -m sensoff --ioff -1.1 --loff 0.5 --skiprows 1 datafile2.csv
Write output to a file instead of stdout
$ python -m sensoff --ioff -1.1 --loff 0.5 --outfile out.csv datafile1.csv
Use a delimiter other than "," and non-default data columns
$ python -m sensoff --ioff -1.1 --loff 0.5 --xcol 2 --ycol 3 --sep " " datafile3.txt
From python:
In [1]: from sensoff import Survey
In [2]: survey = Survey.read_xy("dummy0.csv", skiprows=1)
In [3]: sensor_coords = survey.to_sens_coords(inline_offset=1, lateral_offset=1)
In [4]: print(sensor_coords)
[(470534.417169402, 3759299.464556901), (470534.0298120643, 3759299.8127804487), (470534.3431564087, 3759299.670017598), (470534.9321063309, 3759298.5976250498), (470535.09349569224, 3759298.1006433647), (470534.72614854627, 3759298.08100075), (470534.3293269551, 3759297.1871465445), (470533.71902153065, 3759296.9455717937), (470532.8883022137, 3759296.816779944)]
In [5]: help(Sensor.read_xy)
read_xy(
csvfile, sep: 'str' = ',', xcol: 'int' = 1, ycol: 'int' = 2, skiprows: 'int' = 0
) -> 'Survey'
csvfile : csv filename or object
Delimited file containing GPS coordinates for OTG survey.
xcol : int, optional
Column in datafile with x-coordinates. Default is 1.
ycol : int, optional
Column in datafile with y-coordinates. Default is 2.
sep : str, optional
Delimiter used in coordinate datafile. Default is ",".
skiprows : int, optional
Number of header rows in datafile. Default is 0.
In [6]: help(Sensor.to_sensor_coords)
def to_sensor_coords(
self, inline_offset: int = 0, lateral_offset: int = 0
) -> List[Point]:
inline_offset : float, optional
Sensor offset distance inline with the direction of travel.
Positive in the direction of travel. Default is 0.
lateral_offset : float, optional
Sensor offset distance lateral to the direction of travel.
Positive to the left (facing forward). Default is 0.
Offsets demo:
