topic Re: How can I convert an arcpy geometry object to a shapefile? in Geoprocessing Questions

How can I convert an arcpy geometry object to a shapefile?

SeldaSamiri — Sat, 26 Feb 2011 17:48:00 GMT

Hi there,

I'm quite new to arcpy, so maybe this is stupid question:

I have a script that produces streams as polylines for every branch one line. I use "unsplit line" to merge them to one line with a geometry object as output. This is done several times (several streams) so in the end I have a list with several geometry objects that contain polylines.
Now I want to convert these geometries to a shapefile or geodatabase feature. How can I do this?

CopyFeatures_managements needs a shapefile/Feature as input. Is there a similar tool/opportunity for geometry objects?

Thanks for any help!

Selda

Re: How can I convert an arcpy geometry object to a shapefile?

DanPatterson_Retired — Sat, 26 Feb 2011 19:35:45 GMT

keywords: insertcursor, array
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//002z0000001v000000.htm
has some ideas

Re: How can I convert an arcpy geometry object to a shapefile?

SeldaSamiri — Mon, 28 Feb 2011 07:38:42 GMT

I was hoping that there is an easier and faster way...

Re: How can I convert an arcpy geometry object to a shapefile?

ChrisFox3 — Mon, 28 Feb 2011 14:07:37 GMT

Hi Selda,

You should be able to pass a list of geometries as an input to the copy features tool. In tools that take a feature class or feature layer you can generally subsititute them with geometry objects.

Re: How can I convert an arcpy geometry object to a shapefile?

SeldaSamiri — Tue, 01 Mar 2011 08:23:54 GMT

Hi Chris,

I thought that, too. But what I get is an error message: "Input Data Element: Dataset in_memory\f1F06F212_6D71_42CA_B754_D6EA38AB0E4B does not exist or is not supported"
But it's there and it was the output of the dissolve tool, so it should be ok?!

Any idea?

Selda

Re: How can I convert an arcpy geometry object to a shapefile?

ChrisFox3 — Sat, 11 Dec 2021 18:42:10 GMT

Are you doing something like this in your code?

import arcpy
g = arcpy.Geometry()
geoList = arcpy.Dissolve_management(r'C:\Data\ArcGIS\TemplateData.gdb\USA\states', g)
arcpy.CopyFeatures_management(geoList, r'C:\Data\ArcGIS\TemplateData.gdb\USA\statesDiss")

Re: How can I convert an arcpy geometry object to a shapefile?

SeldaSamiri — Sat, 11 Dec 2021 18:42:13 GMT

Ah, thanks, I did not know, that I have to assign the result to a variable! I tried to use 'g' as input to the arcpy.CopyFeatures_management tool! Now it works.

But now I have another problem:
Inside a loop I append the polylines from the dissolve tool to a list:

 
line_geom = arcpy.Geometry()
lines = arcpy.Dissolve_management(newline, line_geom)
upstream.append(lines[0])

print upstream gives this:

 [<Polyline object at 0x107918d0[0x104daaa0]>,
 <Polyline object at 0xbebd770[0x104ce278]>,
 <Polyline object at 0xbdf6cf0[0xba9c980]>,
 <Polyline object at 0xbe0e750[0x104dad58]>,
 <Polyline object at 0x573d770[0x104ce338]>]

When I now use this list as input to the arcpy.CopyFeatures_management tool I get a shape-file that contains the first polyline in the list 5 times instead of 5 different polylines.

But when I make a shapefile out of every single line from the list like this:

for i in range (0, len(upstream)):
    ln = upstream
    arcpy.CopyFeatures_management(ln, "line" +str(i))

then I get the five different lines correctly. So they are there in the list and they are correct.

How could that happen?

Thank you for your help!
Selda

Re: How can I convert an arcpy geometry object to a shapefile?

ChrisFox3 — Wed, 02 Mar 2011 15:32:34 GMT

I am not sure, could you share all the code from the loop used to create the list of geometries to the CopyFeatures function call?

Re: How can I convert an arcpy geometry object to a shapefile?

SeldaSamiri — Sat, 11 Dec 2021 18:42:16 GMT

this is not the original code as there are many steps inbetween, but it gives the general way I'm doing it.

The overall task was to extract the part of a stream upstream of several sampling sites. I'm doing this in several steps with comparing the elevation in a dem at the stream vertices. As the stream contains of several branches, I need every branch of the upstream part.

In the end I have a list of objects that contains the x/y coordinates for the vertices of the new polyline feature I want to make. Each branch has its own pointlist.

That's the way how I make the polylines:

upstream =[] # for each sampling site a polyline shall be added to this list (one stream contains several branches that are dissolved to one polyline with the dissolve tool in the end)


# do for each sampling site:

for streamsegment_list in sampling_list:


    lineList = []  # for each branch a polyline shall be added to this list


    # do for each branch of the actual stream:

    for segmentlist in streamsegment_list:  # streamsegment_list contains the points for all branches of one stream, segmentlist gives one branch


        pointList = arcpy.Array()         # the points for one branch of the stream-polyline shall be added to this list


        # do for each point of the actual branch:

        for segment in segmentlist:  # segmentlist gives one branch of the stream, segment is an object that contains the x/y coordinates

            PS_pt = arcpy.Point(segment.firstx, segment.firsty)   #firstx and firsty contain the coordinates for the points

            pointList.add(PS_pt)  # add the point to the list


        ln = arcpy.Polyline(pointList)  # make a polyline out of the pointlist (one branch)

        lineList.append(ln)  # append this polyline to the linelist

        ln = None


    line_geom = arcpy.Geometry()

    lines = arcpy.Dissolve_management(lineList, line_geom) # dissolve the branches of one stream to one polyline

    upstream.append(lines[0]) # append this polyline to the upstream-list


# make a new geodatabase feature class for the streams:

arcpy.CopyFeatures_management(upstream, "streams")

but then instead of 5 different polylines I get five times the first polyline in the upstream list as I described.

Re: How can I convert an arcpy geometry object to a shapefile?

ChrisFox3 — Sat, 11 Dec 2021 18:42:19 GMT

And you are saying that after the code to create the geometry list that when you loop through the geometry list and process each individually that you get 5 feature classes each with one feature with unique geometry and if you process the whole geometry list you can one feature class with 5 features each with the same geometry? If that is the case I don't really have any idea what could be causing it and would recommend you contact Technical Support to troubleshoot it further.

# make a new geodatabase feature class for the streams:

for i in range (0, len(upstream)):
    ln = upstream
    arcpy.CopyFeatures_management(ln, "line" +str(i))

arcpy.CopyFeatures_management(upstream, "streams")

Also just to verify you might want to try running the code below just to get more of an idea of the geometry in the list. If the extents are different then the geometries you are creating are different and I am not really sure why they would not be outputed that way when passed to Copy Features.

for g in upstream:
    print "Min X: {0}, Min Y: {1}, Max X: {2}, Max Y: {3}".format(g.extent.XMIN, g.extent.YMIN, g.extent.XMax, g.extent.YMax)

Re: How can I convert an arcpy geometry object to a shapefile?

SeldaSamiri — Tue, 08 Mar 2011 08:31:34 GMT

And you are saying that after the code to create the geometry list that when you loop through the geometry list and process each individually that you get 5 feature classes each with one feature with unique geometry and if you process the whole geometry list you can one feature class with 5 features each with the same geometry?

yes, exactly!

And it get's even stranger: Although I didn't change anything special in the code (I only replaced some fixed pathnames to scratch pathnames) now it works in the python editor. But when I run it as a tool in ArcGIS with GetParametersAsText for the arguments, then it's the same again: 5 times the first polyline in the list.
By the way: It's the same when I use the merge tool instead of CopyFeatures.

Also just to verify you might want to try running the code below just to get more of an idea of the geometry in the list. If the extents are different then the geometries you are creating are different and I am not really sure why they would not be outputed that way when passed to Copy Features.

Your code gives me the following output, so they seem to be really different...:
Min X: 572739.2346, Min Y: 5607458.6527, Max X: 573639.9422, Max Y: 5608326.5093
Min X: 570178.8781, Min Y: 5607424.5708, Max X: 570601.3457, Max Y: 5608190.19
Min X: 571531.150513, Min Y: 5608746.4787, Max X: 572402.529724, Max Y: 5609681.87512
Min X: 569459.7907, Min Y: 5605696.8935, Max X: 569944.0459, Max Y: 5606899.4698
Min X: 569459.7907, Min Y: 5605471.2531, Max X: 569877.6495, Max Y: 5606705.4056

I'm really at a loss...
Yes, I will contact the technical support, maybe they have an idea.

Thanks for trying to help me!

Selda

Re: How can I convert an arcpy geometry object to a shapefile?

ChrisFox3 — Tue, 08 Mar 2011 16:10:41 GMT

Yes at the least I think tech support could get your full code sample and some sample data to reproduce the issue and potentially log a bug. I would be interested to hear what the final outcome is.

Re: How can I convert an arcpy geometry object to a shapefile?

SeldaSamiri — Wed, 04 May 2011 07:06:08 GMT

Weeks of discussion with the tech support did not help, but after the installation of Service pack 2 this problem does not exist anymore...

Cheers,
Selda