Hi,
I have been pointed to a script for calculating the distance between consecutive points and now I need a script or some other way for calculating the bearing (N, NE, NW, etc) between the same points.
Thanks for your help,
Bob
Here is a function:
# North azimuth bearing of a line segment (degrees)
def NorthAzimuth(x1,y1,x2,y2):
degBearing = math.degrees(math.atan2((x2 - x1),(y2 - y1)))
if (degBearing < 0):
degBearing += 360.0
return degBearing
Bruce,
I have calculated azimuths already, what I need now is a script for
converting the numbers to text--N, NE, NW etc. I can't seem to find just
what I want so far. I've been looking at if/then statements in both VB and
Python.
Thanks,
Bob
there are two different field calculator expressions in this link
/blogs/dan_patterson/2016/09/01/distance-calculations-using-the-field-calculator
""" azimuth_to(shape, from_x, from_y)
input: shape field, from_x, from_y
returns: angle between 0 and <360 between a specified point and others
expression: azimuth_to(!Shape!, from_x, from_y)
"""
def azimuth_to(shape, from_x, from_y):
radian = math.atan((shape.centroid.X - from_x)/(shape.centroid.Y - from_y))
degrees = math.degrees(radian)
if degrees < 0:
return degrees + 360.0
else:
return degrees
Expression
azimuth_to(!Shape!,from_x, from_y)
Or this one
""" angle_between(shape)
input: shape field
returns: angle between successive points,
NE +ve 0 to 90, NW +ve 90 to 180,
SE -ve <0 to -90, SW -ve <-90 to -180
expression: angle_between(!Shape!)
"""
x0 = 0.0
y0 = 0.0
angle = 0.0
def angle_between(shape):
global x0
global y0
x = shape.centroid.X
y = shape.centroid.Y
if x0 == 0.0 and y0 == 0.0:
x0 = x
y0 = y
return 0.0
radian = math.atan2((shape.centroid.Y - y0),(shape.centroid.X - x0))
angle = math.degrees(radian)
x0 = x
y0 = y
return angle
Expression
angle_between(!Shape!)
You can mess around with them to get what you want in terms in terms of inputs and outputs.
Dan,
With the scripts you sent earlier I was able to calculate azimuths. What I
need now is a script for converting the numbers to N, NE, NW etc. I can't
seem to find just what I want so far. I've been looking at if/then
statements in both VB and Python.
Thanks,
Bob
On Tue, Sep 20, 2016 at 8:19 PM, Chris Donohue, GISP <geonet@esri.com>
Hi Bob
If you have your angles then you need to test they are within +/- 11.25 degrees of these azimuth breaks:
N:0
NNE:22.5
NE:45
ENE:67.5
... and so on.
BTW, the values are easy to calculate (obviously) but in a shameless plug for Esri's geocoding open file:///C:/Program%20Files%20(x86)/ArcGIS/Desktop10.4/Locators/USAddress.lot.xml in Firefox and navigate to the Spatial Operators elements - very few people know you can prepend spatial operators to street addresses and geocode "off road".