topic Re: geometry help w/ da.InsertCursor in Python Questions

geometry help w/ da.InsertCursor

KevinBell — Mon, 29 Dec 2014 18:35:44 GMT

Ok, I'm stumped! I have a list "xys" that if I do this:

xys.sort()

for i in xys:

print i

I get this: (id, xFrom, yFrom, xTo, yTo)

[225351, 1858897, 889223, 1883031, 882436]

[225396, 1908393, 871758, 1908090, 871791]

[225405, 1899127, 884235, 1885213, 861191]

[225423, 1891186, 878961, 1885811, 881262]

[225435, 1887101, 888042, 1894165, 884325]

[225438, 1888139, 885803, 1888050, 885319]

[225438, 1888139, 885803, 1888081, 884837]

[225441, 1885023, 888542, 1884356, 888364]

[225351, 1858897, 889223, 1883031, 882436]

and then i do this:

for j in xys:

print j

myList = []

myList.append(arcpy.Point(j[1], j[2]))

myList.append(arcpy.Point(j[3], j[4]))

array = arcpy.Array(myList)

polyline = arcpy.Polyline(array)

cursor = arcpy.da.InsertCursor(output, ("SHAPE@"))

cursor.insertRow((polyline,))

print 'inserted row'

I get an empty table... I had this working at one point. Any obvious blunders here?

Re: geometry help w/ da.InsertCursor

DanPatterson_Retired — Mon, 29 Dec 2014 18:47:08 GMT

myList = [] is the list initialization supposed to be inside or outside your 'for' loop?

Re: geometry help w/ da.InsertCursor

KevinBell — Mon, 29 Dec 2014 18:54:07 GMT

myList is supposed to be inside the for loop (I think!)

myList contains 2 point objects that are passed to the polyline object, which is supposed to get inserted.

...but it doesn't do what I want!

If I remove the myList stuff and do this instead:

array = arcpy.Array([arcpy.Point(j[1], j[2]), arcpy.Point(j[3], j[4])])

I get the same results... empty.

Re: geometry help w/ da.InsertCursor

RichardFairhurst — Sun, 12 Dec 2021 04:23:47 GMT

Why is there a comma in the line that reads: cursor.insertRow((polyline,))? Also, shouldn't the field list and polygon array be lists? So try:

for j in xys:
    print j

    myList = []
    myList.append(arcpy.Point(j[1], j[2]))
    myList.append(arcpy.Point(j[3], j[4]))
    array = arcpy.Array(myList)
    polyline = arcpy.Polyline(array)
    cursor = arcpy.da.InsertCursor(output, ["SHAPE@"])
    cursor.insertRow([polyline])
    print 'inserted row'

Re: geometry help w/ da.InsertCursor

KevinBell — Mon, 29 Dec 2014 19:17:56 GMT

Thanks, I tried that, but still no cigar. The code should work. I'm stumped.

Re: geometry help w/ da.InsertCursor

RichardFairhurst — Sun, 12 Dec 2021 04:23:50 GMT

Then go back and make the code more like the InsertCursor help. Also, never create an InsertCursor inside a loop without also deleting it inside the loop. For this code and most code an InsertCursor should only be created once outside the loop and only the insertRow operations should be inside the loop. Then be sure to delete the InsertCursor, since there is no other correct way to stop it and release its locks. Failure to delete the cursor in your previous code may be the reason why the cursor never completes and refuses to show the records it created, since it still thinks it is waiting to create more records and you have opened many cursors on the same source.

cursor = arcpy.da.InsertCursor(output, ["SHAPE@"])

for j in xys:
    print j

    array = arcpy.Array([arcpy.Point(j[1], j[2]), arcpy.Point(j[3], j[4])])
    polyline = arcpy.Polyline(array)
    cursor.insertRow([polyline])
    del array
    del polyline
    print 'inserted row'

del cursor

Re: geometry help w/ da.InsertCursor

KevinBell — Mon, 29 Dec 2014 19:55:34 GMT

Richard, that is definitely much cleaner, but it's still not working.

In the loop I've even printed the type(j[1]) etc, and they all are 'int', so I've verified that I'm not feeding it bad data.

Re: geometry help w/ da.InsertCursor

RichardFairhurst — Mon, 29 Dec 2014 20:00:23 GMT

The missing part of your code that most likely is part of the problem is that you have not shown what the output variable is assigned. Maybe it is writing somewhere else than where you think it is writing, depending on the workspace settings, fc name, etc. Since it is not throwing an error, it probably is a valid output, but I have wasted plenty of time checking what I thought I told my code to do when I actually told my code to do something different.

Re: geometry help w/ da.InsertCursor

XanderBakker — Sun, 12 Dec 2021 04:23:53 GMT

If I run this code in ArcGIS 10.2.2, it runs just fine and creates the polylines.

import arcpy
fc = r"C:\Forum\DistLinePol\test.gdb\Polyline2"

xys = [[225351, 1858897, 889223, 1883031, 882436],
       [225396, 1908393, 871758, 1908090, 871791],
       [225405, 1899127, 884235, 1885213, 861191],
       [225423, 1891186, 878961, 1885811, 881262],
       [225435, 1887101, 888042, 1894165, 884325],
       [225438, 1888139, 885803, 1888050, 885319],
       [225438, 1888139, 885803, 1888081, 884837],
       [225441, 1885023, 888542, 1884356, 888364],
       [225351, 1858897, 889223, 1883031, 882436]]

with arcpy.da.InsertCursor(fc, ("SHAPE@")) as cursor:
    for j in xys:
        array = arcpy.Array()
        array.add(arcpy.Point(j[1], j[2]))
        array.add(arcpy.Point(j[3], j[4]))
        polyline = arcpy.Polyline(array)
        cursor.insertRow((polyline, ))

Richard Fairhurst‌; there are many examples where the list of fields is handled as tuple and the comma in "(polyline, )" is to create the tuple.

Re: geometry help w/ da.InsertCursor

KevinBell — Mon, 29 Dec 2014 20:09:19 GMT

The exact same code doesn't insert at 10.3!

Re: geometry help w/ da.InsertCursor

XanderBakker — Sun, 12 Dec 2021 04:23:55 GMT

interesting, but annoying... If I look at the help of the da.InsertCursor at 10.3:

http://desktop.arcgis.com/en/desktop/latest/analyze/arcpy-data-access/insertcursor-class.htm#C_GUID-DA74F0E0-2D67-472A-84B3-CB594A43750B

... I see that they use (as Richard Fairhurst‌ suggests) a list for the fields and insert the row as list. So maybe if you make some minor changes it will work in 10.3 (I can't verify this until next week):

import arcpy
fc = r"C:\Forum\DistLinePol\test.gdb\Polyline2"

xys = [[225351, 1858897, 889223, 1883031, 882436],
      [225396, 1908393, 871758, 1908090, 871791],
      [225405, 1899127, 884235, 1885213, 861191],
      [225423, 1891186, 878961, 1885811, 881262],
      [225435, 1887101, 888042, 1894165, 884325],
      [225438, 1888139, 885803, 1888050, 885319],
      [225438, 1888139, 885803, 1888081, 884837],
      [225441, 1885023, 888542, 1884356, 888364],
      [225351, 1858897, 889223, 1883031, 882436]]

with arcpy.da.InsertCursor(fc, ["SHAPE@"]) as cursor:
    for j in xys:
        array = arcpy.Array()
        array.add(arcpy.Point(j[1], j[2]))
        array.add(arcpy.Point(j[3], j[4]))
        polyline = arcpy.Polyline(array)
        cursor.insertRow([polyline])

Re: geometry help w/ da.InsertCursor

DanielSmith — Mon, 29 Dec 2014 20:25:37 GMT

inserts worked for me at 10.3.

refresh in catalog maybe?

are the coordinates posted way out of bounds for the coordinate system?

Re: geometry help w/ da.InsertCursor

RichardFairhurst — Mon, 29 Dec 2014 20:38:41 GMT

I agree with Daniel that the code Xander posted (using tuples or lists) works with Python 2.7.8 and ArcMap 10.3. I get the same results he showed. The coordinates work even with my default state plane coordinate system which is not really designed for this data.

Sounds like a reboot is in order if it is not working.

Re: geometry help w/ da.InsertCursor

KevinBell — Mon, 29 Dec 2014 21:59:16 GMT

Reinstalling now. My upgrade must have gone wrong.

Thanks everyone! The application here's pretty cool. This will be like a live spider diagram showing police officers converging on a call for assistance.

Re: geometry help w/ da.InsertCursor

DanielSmith — Mon, 29 Dec 2014 22:13:47 GMT

cool. share a final output when you can .

Re: geometry help w/ da.InsertCursor

KevinBell — Tue, 30 Dec 2014 17:45:49 GMT

Ok, my police "calls for service" map is done with lines showing who's assigned to whatever call! Thanks for your help everyone. (this refreshes every 30 seconds)

Re: geometry help w/ da.InsertCursor

XanderBakker — Tue, 30 Dec 2014 22:03:55 GMT

Cool! Nice Work!