topic Re: Toolbox Script to Make a Line on the map in Python Questions

Toolbox Script to Make a Line on the map

GregDelapaix — Wed, 27 Apr 2011 04:45:36 GMT

Hey all-
I am trying to place the following script into a toolbox I created. The idea is that it receives user input for x and y origins (decimal degrees), distance and angle. Distance, along with origin_x and origin_y are linear measurements, angle is set as 'any value'- I'm not sure if this is correct, but the idea with angle is that it would be a number from 0 to 360 with North being 0, West being 90, etc. I also want to make sure the script references the map properly, to create a line using the input parameters.

Here is my script so far, when I run it I get the following error:
<type 'exceptions.TypeError'>: unsupported operand type(s) for /: 'unicode' and 'float'
Failed to execute (Script). I would GREATLY appreciate any help

Code is as follows:

import arcpy
from math import radians, sin, cos, pi

origin_x = arcpy.GetParameterAsText(0)
origin_y = arcpy.GetParameterAsText(1)
distance = arcpy.GetParameterAsText(2)
angle = arcpy.GetParameterAsText(3)

# convert latitude and longitude to radians
origin_x = origin_x/(180/pi)
origin_y = origin_y/(180/pi)

# calculate offsets with light trig
(disp_x, disp_y) = (distance * sin(radians(angle)), distance * cos(radians(angle)))
(end_x, end_y) = (origin_x + disp_x, origin_y + disp_y)

output = "offset-line.shp"
arcpy.CreateFeatureClassManagement("G:\Delapaix\line_connect\line_connect", output, "Polyline")
cur = arcpy.InsertCursor(output)
lineArray = arcpy.Array()

# start point
start = arcpy.Point()
(start.ID, start.X, start.Y) = (1, origin_x, origin_y)
lineArray.add(start)

# end point
end = arcpy.Point()
(end.ID, end.X, end.Y) = (2, end_x, end_y)
lineArray.add(end)

# write feature to the shapefile
feat = cur.newRow()
feat.shape = lineArray
cur.insertRow(feat)

# code for buffering the line and including features in buffer zone would go here

# yes, this shouldn't really be necessary
lineArray.removeAll()

Re: Toolbox Script to Make a Line on the map

GregDelapaix — Wed, 27 Apr 2011 04:54:23 GMT

Sorry- forgot to mention that the purpose of the script is to create a line on the map, though most probably could figure that out from looking at the code...

Re: Toolbox Script to Make a Line on the map

DanPatterson_Retired — Wed, 27 Apr 2011 10:30:28 GMT

You will note that your
origin_x variable is a text parameter (ie GetParameterAsText), hence, you need to cast it to a float value before performing any math operations using it. This line:

origin_x = origin_x/(180/pi)

should be

origin_x = float(origin_x) / (180 / pi)

You will need to correct the others in the same fashion.

Re: Toolbox Script to Make a Line on the map

GregDelapaix — Wed, 27 Apr 2011 20:40:04 GMT

@Dan-
Thank you, that resolved my error. Now, I am getting the following:

<type 'exceptions.AttributeError'>: 'module' object has no attribute 'CreateFeatureClass'
Failed to execute (Script).

Not sure how to fix this- do I need to create a gdb for the FeatureClass to write to?
The error looks like arcpy has no CreateFeatureClass, which is not the case according to Esri
(http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//00170000002p000000.htm)

'''
Created on Apr 24, 2011

@author: gregdelapaix
'''
import arcpy
from arcpy import env
from math import radians, sin, cos, pi

#Set workspace
env.workspace = "G:\Delapaix\Geog_586_FinalProject\line_connect"

origin_x = arcpy.GetParameterAsText(0)
origin_y = arcpy.GetParameterAsText(1)
distance = arcpy.GetParameterAsText(2)
angle = arcpy.GetParameterAsText(3)

# convert latitude and longitude to radians
origin_x = float(origin_x)/(180/pi)
origin_y = float(origin_y)/(180/pi)

# calculate offsets with light trig
(disp_x, disp_y) = (float(distance) * sin(radians(float(angle))), float(distance) * cos(radians(float(angle))))
(end_x, end_y) = (float(origin_x) + disp_x, float(origin_y) + disp_y)

output = "offset-line.shp"
arcpy.CreateFeatureClass_management("G:\Delapaix\Geog_586_FinalProject\line_connect", output, "Polyline")
cur = arcpy.InsertCursor(output)
lineArray = arcpy.Array()

# start point
start = arcpy.Point()
(start.ID, start.X, start.Y) = (1, origin_x, origin_y)
lineArray.add(start)

# end point
end = arcpy.Point()
(end.ID, end.X, end.Y) = (2, end_x, end_y)
lineArray.add(end)

# write feature to the shapefile
feat = cur.newRow()
feat.shape = lineArray
cur.insertRow(feat)

# code for buffering the line and including features in buffer zone would go here

# yes, this shouldn't really be necessary
lineArray.removeAll()

Re: Toolbox Script to Make a Line on the map

DarrenWiens2 — Wed, 27 Apr 2011 20:49:58 GMT

Everything in Arcpy is case sensitive, so you should try: CreateFeatureclass_management

Re: Toolbox Script to Make a Line on the map

GregDelapaix — Wed, 27 Apr 2011 21:19:23 GMT

@dkwiens Thank you! I stared at the esri documentation for half an hour and didn't see that...

I have another error I am unable to figure out, mainly because I'm new to Python, ArcPy, etc.
Here it is:

<class 'arcgisscripting.ExecuteError'>: ERROR 000354: The name contains invalid characters
Failed to execute (CreateFeatureclass).

Failed to execute (Script).

What might these invalid characters be?

Also, I am concerned about one other thing, which is that the script doesn't contain information for distance in terms of units- I want it to be in miles- seems like something is missing for the script to create the dataset, let alone place the line on the map with the right units

Any further help GREATLY appreciated

GD

Re: Toolbox Script to Make a Line on the map

DanPatterson_Retired — Wed, 27 Apr 2011 21:21:50 GMT

Not to mention, that Python requires all paths to be forward slashes "/" and not backslashes, or use double backslashes "\\" or the "raw" identifier (see python help) if you insist in using backslashes

Re: Toolbox Script to Make a Line on the map

GregDelapaix — Wed, 27 Apr 2011 21:34:18 GMT

Thanks Dan, that did cross my mind at one point though I forgot. I'm using ArcMap on a remote server via a Citrix plug-in, and I am used to forward slashes, but I thought for the Windows machine I maybe needed backslashes... oi

Re: Toolbox Script to Make a Line on the map

GregDelapaix — Wed, 27 Apr 2011 22:25:17 GMT

.....still looking for any help on invalid characters with CreateFeatureclass_management, still getting the error after correcting the backslash mistake...
GD

Re: Toolbox Script to Make a Line on the map

DarrenWiens2 — Thu, 28 Apr 2011 01:56:51 GMT

The shapefile you're trying to make has an invalid name (output = "offset-line.shp"). No hyphens allowed.

Interestingly, I was able to make a shapefile with a hyphenated name by right-clicking and choosing new shapefile. I didn't try to do anything with it, though, so who knows if it's a functional shapefile...

Re: Toolbox Script to Make a Line on the map

GregDelapaix — Thu, 28 Apr 2011 03:46:45 GMT

@dkwiens
Thank you that fixed it!

If possible, I am in need of further assistance- I am attempting to make the line appear on a map which is in the same folder the shapefile is created in. As it is now, it creates the shapefile, but not the line on a map. Do I need to create a geodatabase to place the shapefile in? Otherwise I'm not sure about the script being able to detect the projection/coordinate system. I'm also not sure about making sure the units for the length of the line are consistent, in this case miles
Here is my script as it currently stands:

'''
Created on Apr 24, 2011

@author: gregdelapaix
'''
import arcpy
from arcpy import env
from math import radians, sin, cos, pi

#Set workspace
env.workspace = "G:\\Delapaix\\Geog_586_FinalProject\\line_connect"

origin_x = arcpy.GetParameterAsText(0)
origin_y = arcpy.GetParameterAsText(1)
distance = arcpy.GetParameterAsText(2)
angle = arcpy.GetParameterAsText(3)

# convert latitude and longitude to radians
origin_x = float(origin_x)/(180/pi)
origin_y = float(origin_y)/(180/pi)

# calculate offsets with light trig
(disp_x, disp_y) = (float(distance) * sin(radians(float(angle))), float(distance) * cos(radians(float(angle))))
(end_x, end_y) = (float(origin_x) + disp_x, float(origin_y) + disp_y)

output = "offsetLine.shp"
arcpy.CreateFeatureclass_management("G:\\Delapaix\\Geog_586_FinalProject\\line_connect", output, "Polyline")
cur = arcpy.InsertCursor(output)
lineArray = arcpy.Array()

# start point
start = arcpy.Point()
(start.ID, start.X, start.Y) = (1, origin_x, origin_y)
lineArray.add(start)

# end point
end = arcpy.Point()
(end.ID, end.X, end.Y) = (2, end_x, end_y)
lineArray.add(end)

# write feature to the shapefile
feat = cur.newRow()
feat.shape = lineArray
cur.insertRow(feat)

# code for placing the line on the map here(?)
# code for buffering the line and including features in buffer zone would go here

# should I remove this?
lineArray.removeAll()