topic Re: Calculating angles using ArcGIS Desktop 10.2 in Geoprocessing Questions

Calculating angles using ArcGIS Desktop 10.2

BrianVann — Thu, 21 Jan 2016 19:17:09 GMT

I need to find angles of streets where they intersect with roadways covering the entire state. Does anyone have a method and/or tools in mind?

Re: Finding angles using ArcGIS Desktop 10.2

WesMiller — Thu, 21 Jan 2016 19:26:57 GMT

if you have an Advanced License you could use the Near—Help | ArcGIS for Desktop

Re: Finding angles using ArcGIS Desktop 10.2

BrianVann — Sat, 23 Jan 2016 20:13:01 GMT

Thanks for the help Wes!

It looks as though this tool returns angle values in relation to North, South, East, or West. I am looking for a method that returns an angle where 2 lines intersect. In addition, I have a least a few hundreds of thousands of intersecting lines to measure those angles... We are trying to find all the intersecting roadways in the state that are at an angle of less than 40 degrees, where they intersect, and run crash rates and analyses. Do you still think this tool will do the job of measuring those angles?

Thanks again for the prompt response!

Re: Calculating angles using ArcGIS Desktop 10.2

DanPatterson_Retired — Sat, 23 Jan 2016 20:33:31 GMT

You might want want to move this to Geoprocessing GeoNet Community Structure this space is for help on GeoNet and how to use it.

Re: Finding angles using ArcGIS Desktop 10.2

WesMiller — Sun, 24 Jan 2016 16:25:20 GMT

Attached is a model that should accomplish what you are trying to do.If you'll add your streets layer and leave the defaults it should produce a point file at each intersection that has an angle between 5 and 40. I made these parameters so they could be adjusted, the other distance field is how far back from the intersection do you want to check the angle, 50 was used you may want smaller. The model will need an Advanced license to run.

Re: Calculating angles using ArcGIS Desktop 10.2

BrianVann — Mon, 25 Jan 2016 17:49:05 GMT

Wes,

Thanks!

I ran the model and it failed with this error:

Assembling Features...
Succeeded at Mon Jan 25 11:06:26 2016 (Elapsed Time: 2 minutes 4 seconds)
Executing (Generate Near Table): GenerateNearTable in_memory\roadsIntersect in_memory\Roads_Intersect_Buffer_Inter in_memory\nearTable "51 Feet" NO_LOCATION ANGLE ALL 0 PLANAR
Start Time: Mon Jan 25 11:06:27 2016
Determining data processing extents...
Building a neighborhood index from the Near Features...
Generating Near Table...
Found 346 feature(s) within 51.000000
Succeeded at Mon Jan 25 11:06:27 2016 (Elapsed Time: 0.56 seconds)
Executing (findLessThanAngle): findLessThanAngle 50 5 in_memory\roadsIntersect in_memory\nearTable
Start Time: Mon Jan 25 11:06:27 2016
Running script findLessThanAngle...
Failed script findLessThanAngle...

Traceback (most recent call last):
File "Y:\GISData\Tools\FindAngletoolbox\findAngle.tbx#findLessThanAngle.py", line 37, in <module>
NameError: name 'each' is not defined

Failed to execute (findLessThanAngle).
Failed at Mon Jan 25 11:06:28 2016 (Elapsed Time: 0.23 seconds)

I deleted the "each" out of the python code, ran it, but it only gave me 22 intersecting roadways with angles of < than 50 degrees out of 2299 total...I wasn't sure if it was my python code editing that gave me the short list.

I know very little about python. It is in my toolbox of things to do, no pun intended.

Other than that, it does look promising!

Thanks again for your help!

Re: Calculating angles using ArcGIS Desktop 10.2

WesMiller — Mon, 25 Jan 2016 20:09:00 GMT

Would you be willing to share a portion of your data? 22 is far less than i expected for a state wide search. I'll check the code against your data. I tested this code against county data and returned over 200.

Re: Calculating angles using ArcGIS Desktop 10.2

BrianVann — Wed, 27 Jan 2016 17:35:05 GMT

Wes,

Sorry for the delayed response. Been kind of busy.

Yes, I have attached a county with a roadway layer here. I have tried running the model several more times and now I cannot get any results at all to show in the table of contents. Did I mess something up?

I have also attached the model again here to verify whether or not I have corrupted it... I even tried removing the original model and reinstalling it into the "Toolbox" in ArcMap...

Thanks,

Brian

Re: Calculating angles using ArcGIS Desktop 10.2

BrianVann — Wed, 27 Jan 2016 17:50:12 GMT

The last reply didn't have an "attach" tool located on it...

Attached is a county dataset. As I said earlier, the model will not offer any results on this county either, although it does run and complete.

I have also attached here again the "findAngle" tool to check if I have corrupted it...

Thanks again for your help!

Brian

Re: Calculating angles using ArcGIS Desktop 10.2

BrianVann — Wed, 27 Jan 2016 19:10:43 GMT

Wes,

I edited the model again using file geodatabases instead of the "in_memory" modules and YES, the model completes and stores the intersection locations that have the upper and lower limit angles.

Awesome! I HAVE to learn Python!!

Thanks!!

Re: Calculating angles using ArcGIS Desktop 10.2

WesMiller — Wed, 27 Jan 2016 20:31:26 GMT

Glad to here it!

Re: Calculating angles using ArcGIS Desktop 10.2

BrianVann — Thu, 04 Feb 2016 19:45:28 GMT

Hi Wes,

It's me again with problems with the angles of roadways. I have found the tool you provided, which is pretty awesome, has the tendency to produce a point on angles that are greater than the parameters set in the model. Although the tool does find these angles at intersections, it tends to produce some outside the parameters set. These extra points that are suppose to signify angles within the tool parameters are always located where buffers overlap. What do you think? Can these be removed somehow via your tool?

Thanks!

Re: Calculating angles using ArcGIS Desktop 10.2

WesMiller — Thu, 04 Feb 2016 20:07:42 GMT

Did you try using a smaller buffer size? This may get the desired results.

Edit:

I just checked the model you should also change the search distance in the "Generate Near Table" tool to match the buffer size you use. Originally i used the buffer distance + 1 to make sure i was far enough out to capture the intended points.

Re: Calculating angles using ArcGIS Desktop 10.2

DarrenWiens2 — Fri, 10 Dec 2021 23:13:17 GMT

This post has been on my mind for a while, and here's what I came up with. I suspect it's quite similar to Wes' previously posted solution, but works for all license levels:

>>> import os
... fc = "myLines"
... sr = arcpy.Describe(fc).spatialReference
... radius = 50
... out_fc = r'in_memory\points'
... int_pt = r'in_memory\int_pt'
... arcpy.Intersect_analysis(fc,int_pt,output_type='POINT')
... diss_int_pt = r'in_memory\diss_int_pt'
... arcpy.Dissolve_management(int_pt,diss_int_pt,'#',[["FID","MIN"]],"SINGLE_PART")
... buff = r'in_memory\buff'
... arcpy.Buffer_analysis(diss_int_pt,buff,str(radius) + ' METERS')
... buff_line_int = r'in_memory\buff_line_int'
... arcpy.Intersect_analysis([buff,fc],buff_line_int,output_type='POINT')
... sing_buff_line_int = r'in_memory\sing_buff_line_int'
... arcpy.MultipartToSinglepart_management(buff_line_int,sing_buff_line_int)
... new_points = {}
... with arcpy.da.SearchCursor(diss_int_pt,['OID@','SHAPE@'],spatial_reference=sr) as cursor1:
...    for row1 in cursor1:
...        cent_pt = row1[1].centroid
...        angs = []
...        with arcpy.da.SearchCursor(sing_buff_line_int,'SHAPE@','\"FID_buff\" = ' + str(row1[0]),spatial_reference=sr) as cursor2:
...            for row2 in cursor2:
...                buff_pt = row2[0].centroid
...                dx = cent_pt.X - buff_pt.X
...                dy = cent_pt.Y - buff_pt.Y
...                if dx < 0 and dy <= 0:
...                    ang = math.degrees(math.atan(abs(dy/dx)))
...                if dx <= 0 and dy > 0:
...                    ang = math.degrees(math.atan(abs(dx/dy))) + 270
...                if dx > 0 and dy >= 0:
...                    ang = math.degrees(math.atan(abs(dy/dx))) + 180
...                if dx >= 0 and dy < 0:
...                    ang = math.degrees(math.atan(abs(dx/dy))) + 90
...                angs.append(ang)
...        angs.sort()
...        for i in range(1,len(angs)):
...            mid_ang = ((angs + angs[i-1])/2)
...            ang_diff = angs - angs[i-1]
...            new_x = cent_pt.X + (radius * math.cos(math.radians(mid_ang)))
...            new_y = cent_pt.Y + (radius * math.sin(math.radians(mid_ang)))
...            new_point = arcpy.PointGeometry(arcpy.Point(new_x, new_y),sr)
...            new_points[str(row1[0]) + '_' + str(i)] = [ang_diff,new_point]
...        mid_ang = (((360-angs[-1]) + angs[0])/2) - (360-angs[-1])
...        ang_diff = (360-angs[-1]) + angs[0]
...        new_x = cent_pt.X + (radius * math.cos(math.radians(mid_ang)))
...        new_y = cent_pt.Y + (radius * math.sin(math.radians(mid_ang)))
...        new_point = arcpy.PointGeometry(arcpy.Point(new_x, new_y),sr)
...        new_points[str(row1[0]) + '_0'] = [ang_diff,new_point]
... arcpy.CreateFeatureclass_management(os.path.dirname(out_fc),os.path.basename(out_fc),'POINT',spatial_reference=sr)
... arcpy.AddField_management(out_fc,'FID_buff',"LONG")
... arcpy.AddField_management(out_fc,'ANGLE',"DOUBLE")
... iCursor = arcpy.da.InsertCursor(out_fc,['SHAPE@','FID_buff','ANGLE'])
... for k,v in new_points.iteritems():
...    row = [v[1],k.split('_')[0],v[0]]
...    iCursor.insertRow(row)

Re: Calculating angles using ArcGIS Desktop 10.2

WesMiller — Fri, 12 Feb 2016 00:58:03 GMT

Darren NICE!

Does your second intersect create points where the buffers overlap see above from Brian? I told Brian to reduce the buffer size and that should work, but like you I've thought a lot about this one too. In retrospect i think i would add a select by location and just gather the points that intersect the streets and calculate from there. After looking at your code i feel like i got off easy using the near tool to grab the angles of the line and doing light math to calculate the angles.

Re: Calculating angles using ArcGIS Desktop 10.2

DarrenWiens2 — Fri, 12 Feb 2016 17:29:05 GMT

The script makes points on each buffer in isolation, so there is no influence from any other buffer. I agree that the buffer size should be as low as reasonable. You would run into problems if the buffer overlapped other intersections or parallel streets.

Good:

Bad:

Re: Calculating angles using ArcGIS Desktop 10.2

BrianVann — Mon, 15 Feb 2016 02:28:43 GMT

Darren,

I also thought of completing this task similar to what your image shows. It seems it should be somewhat simple; buffer points at intersections by 100 ft, convert the buffers to a line, and simply clip the arc of each resulting line where the roads intersect the circular line. Any circular line that has been clipped from a roadway line that has a arc length between the parameters of 1ft to 122.17ft (at a radius of 100ft) would be an intersection where a roadway has an intersecting roadway of less than 70 degrees. The problem I had with this method is that the process returned many arcs lengths from the buffered lines that were actually not due to the clipping function but rather due to the fact that they were not completely closed lines and thus left short arcs...

Your model looks very promising and seems a good method to use; however, I keep getting error messages when put into the python window. I haven’t much experience with python.

example: Runtime error Traceback (most recent call last): File "<string>", line 9, in <module> File "c:\program files (x86) \arcgis\desktop10.2\arcpy\arcpy\management.py", line 4021, in Dissolve raise e ExecuteError: ERROR 000369: Invalid input field(s)

Hope this makes sense...

And, thanks for the help!!

Re: Calculating angles using ArcGIS Desktop 10.2

BrianVann — Wed, 17 Feb 2016 03:10:54 GMT

Darren,

I finally got the script to work by exporting the fc into a shapefile.

And now receiving this error message:

Runtime error Traceback (most recent call last): File "<string>", line 49, in <module> File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\management.py",

line 3052, in AddField raise e ExecuteError: ERROR 000732: Input Table: Dataset in_memory\points does not exist or is not supported

Brian

Re: Calculating angles using ArcGIS Desktop 10.2

JeremyMullins4 — Fri, 01 Apr 2016 17:45:44 GMT

Darren,

I'm getting the following issue running your python script:

Traceback (most recent call last):

File "C:\Users\jmullins\Desktop\Test.py", line 3, in <module>

sr = arcpy.Describe(fc).spatialReference

NameError: name 'arcpy' is not defined

I threw an import arcpy underneath import os, and now I am getting this error:

Traceback (most recent call last):

File "C:\Users\jmullins\Desktop\Test.py", line 8, in <module>

arcpy.Intersect_analysis(fc,int_pt,output_type='POINT')

File "C:\Program Files (x86)\ArcGIS\Desktop10.4\ArcPy\arcpy\analysis.py", line 289, in Intersect

raise e

RuntimeError: Object: Error in executing tool

I apologize for being inept at python scripting, and I appreciate any help you (or anyone else) can provide. Thanks!

Re: Calculating angles using ArcGIS Desktop 10.2

WesMiller — Fri, 01 Apr 2016 18:42:24 GMT

Put the below at the top of the script

import arcpy