My preference is always to script it out with arcpy, especially in cases like this where using the GUI could quickly become cumbersome.
ArcGIS 10.3 introduces a new method for point geometries that fits the bill for this task: arcpy.PointGeometry.pointFromAngleAndDistance. Unfortunately, that likely isn't going to help you out here and now unless you are testing the prerelease version of it. In the absence of that new method, you can roll your own using basic trigonometry. Since we are rolling our own, I think it makes sense to create a function to go one step further and build the line:
def linefromPolarCoord(angle, distance, point, spatialReference=None):
X = distance * math.cos(math.radians(90 - angle))
Y = distance * math.sin(math.radians(90 - angle))
return arcpy.Polyline(
arcpy.Array([point, arcpy.Point(point.X + X, point.Y + Y)]),
spatialReference
)
The above function assumes basic 2D/projected data, nothing fancy with 3D distances or lines. The angle is degrees, distance is in units of the projection (meters for UTM), point is an arcpy.Point, and spatialReference is an arcpy.spatialReference for the projection being used.
Since you want to work in decimal increments and Python's range is integer based, I suggest rolling your own decimal-based sequence function. I like the accepted solution of drange on the following StackExchange question: Python decimal range() step value.
Assuming you have the 500 points in a point feature class (pointsFC) and a single water body polygon in a feature class (waterbodyFC), the following code might get you in the ballpark:
alpha = 22.5
distance =
pointsFC =
waterbodyFC =
fetchesTable = 'fetches'
arcpy.CreateTable_management("in_memory", fetchesTable)
arcpy.AddField_management(fetchesTable, "POINTID", "LONG")
arcpy.AddField_management(fetchesTable, "FETCH_ANGLE","DOUBLE")
arcpy.AddField_management(fetchesTable, "FETCH_DISTANCE","DOUBLE")
with arcpy.da.SearchCursor(waterbodyFC, "SHAPE@") as searchCur:
for row in searchCur:
pn = row[0]
SR = pn.spatialReference
with arcpy.da.InsertCursor(
fetchesTable,["POINTID", "FETCH_ANGLE", "FETCH_DISTANCE"]
) as insertCur:
with arcpy.da.SearchCursor(
pointsFC,["OID@","SHAPE@"]
) as searchCur:
for row in searchCur:
OID = row[0]
pt = row[1].firstPoint
for i in drange(0, 360, alpha):
pl = linefromPolarCoord(i, distance, pt, SR).intersect(pn,2)
insertCur.insertRow([OID, i, pl.length])
The above code assumes the points are in the water body, and you are interested in the distance to the edge of the water body, i.e., the shore. Using intersect might not be the best option if the water body wraps back on itself or has lots of bays because that could give a length that is more than the length to the shore. That said, the code is meant to demonstrate a workflow that can be scripted.
My original code would generate a distance of 266.7m for the given point on the lake above with a fetch angle of 337.5 degrees. My guess is that you don't want the total length of the line, but the length of the first part ( Part(0) ) of the line, which is 96.16m.
