topic Re: converting contours to points in Geoprocessing Questions

converting contours to points

KONPETROV — Tue, 13 Jan 2015 22:13:38 GMT

Hello i have a mosaic dem and i have extracted contours wit interval = 2 meters. Now i want to convert contours to points xyz with distance of 1 meter from one point to another at the same contour line for each contour, any suggestion?

Re: converting contours to points

XanderBakker — Sat, 11 Dec 2021 22:44:49 GMT

You can use some python to obtain the points you want:

import arcpy, os

fc_in = r"C:\Forum\Pasture\gdb\Contours.gdb\contours2"
fc_out = r"C:\Forum\Pasture\gdb\Contours.gdb\contour_pnts03"
fld_contour = "Contour"
interval = 1

# create empty output featureclass
sr = arcpy.Describe(fc_in).spatialReference
out_ws, out_name = os.path.split(fc_out)
arcpy.CreateFeatureclass_management(out_ws, out_name, "POINT", fc_in, "DISABLED", "DISABLED", sr)

# add field with contour value to output fc
arcpy.AddField_management(fc_out, fld_contour, "DOUBLE")

cnt = 0
with arcpy.da.InsertCursor(fc_out, ("SHAPE@", fld_contour)) as curs_out:
    with arcpy.da.SearchCursor(fc_in, ("SHAPE@", fld_contour)) as curs_in:
        for row_in in curs_in:
            polyline = row_in[0]
            contour = row_in[1]
            max_len = polyline.length
            d = 0
            while d < max_len:
                pnt = polyline.positionAlongLine(d, False)
                curs_out.insertRow((pnt.firstPoint, contour, ))
                cnt += 1
                if cnt % 100 == 0:
                    print "Processing point: {0}".format(cnt)
                # pnt.firstPoint
                d += interval
            curs_out.insertRow((polyline.lastPoint, contour, ))
            cnt += 1

Change the lines 3 and 4 to point to your input featureclass and the output you want to create.

Re: converting contours to points

DanPatterson_Retired — Tue, 13 Jan 2015 23:16:03 GMT

If you have ArcMap 10.2.x at the Advanced level try the Densify tool or try this version for lower license levels, then convert to points

Re: converting contours to points

KONPETROV — Wed, 14 Jan 2015 06:25:54 GMT

thanks a lot for your help. I tried your code and i only change the path for my files (line 3 & 4) but when i run the code i get that message.

Runtime error

Traceback (most recent call last):

File "<string>", line 8, in <module>

NameError: name 'os' is not defined

What should i do? Isn't there any solution without code?

Re: converting contours to points

KONPETROV — Wed, 14 Jan 2015 06:33:06 GMT

i corrected it and now i get

Parsing error Indentation Error: expected an indented block (line 18)

Re: converting contours to points

KONPETROV — Wed, 14 Jan 2015 06:49:00 GMT

now an error 000732 for some reason

Re: converting contours to points

DanPatterson_Retired — Wed, 14 Jan 2015 07:23:42 GMT

the file and/or its path is not supported from the help topic Error 000732 either something is wrong with your file type, you incorrectly specified the path and/or you copied and pasted the code incorrectly

Re: converting contours to points

XanderBakker — Wed, 14 Jan 2015 12:07:23 GMT

Can you show what you specified for lines 3 and 4 (your input and output featureclass)? Did you try Dan Patterson‌ suggestion?

Re: converting contours to points

KONPETROV — Wed, 14 Jan 2015 19:21:08 GMT

Mr Xander Bakker thanks again, I tried again your code for an area of 10^2 km to find points with distance of 1 meter /contour / 2240 contours and it keeps running for over 6 hours by now. It has calculated already 15.000.000 points. I think is working fine, i haven't already see the result, but i will post it. On the other hand I tried both Dan Patterson suggestions (Densify & installation of tool for lower lic. levels) but i get a script error with that tool, or after the procession of densify i cannot see the file of contour on my worrkspace and on attribute table nothing is changed. I haven't figure it out until now what is wrong with densify.

! There is a toll (Station Points) at ET Geowizard but is not free.

! There is also construction points of Editor but you must do it manually for each polyline.

Any other suggestion for tools Arc already has? thank you both

Re: converting contours to points

XanderBakker — Wed, 14 Jan 2015 20:03:57 GMT

I am glad it is working, and yes it can be a long process depending on the number of points that need to be generated.

If you can use the standard Densify tool as Dan suggested, you could use the Feature Vertices to Points tool. This tool can convert a line into points, but will only convert the existing vertices (not create any new ones)

Re: converting contours to points

KONPETROV — Wed, 14 Jan 2015 20:37:13 GMT

Thank you Mr Baker, but there isn't any tool available in gis specific for that task? I only found ET Geowizard's tool (station points) and nothing else. How can that be?

Re: converting contours to points

XanderBakker — Wed, 14 Jan 2015 21:04:13 GMT

Good question. At first I thought that this should be available as standard tool in ArcGIS, but that seems not to be the case. Maybe it is because you can string the Densify and Feature Vertices to Points tools together and get the result, but this is not for all licenses available.

Re: converting contours to points

DanPatterson_Retired — Wed, 14 Jan 2015 22:07:54 GMT

It works fine with shapefiles in folders...geodatabases aren't supported

Re: converting contours to points

KONPETROV — Wed, 14 Jan 2015 22:25:44 GMT

in which line i can change the code to do the procession for points every 3 meter for example.

and in which point i can define to run the procession for contour >1000 meters also.

That's my last question, you helped me a lot, thank you very much.

Re: converting contours to points

XanderBakker — Sat, 11 Dec 2021 22:44:52 GMT

The code would look like the code below. Notice the following changes:

Line 6 holds the interval, I changed it from 1 to 3, so now it picks points every 3 meters on each contour line.
Line 14 contains a where clause that filters the contour lines with Contour > 1000
Line 21 applies the where clause

import arcpy, os

fc_in = r"C:\Forum\Pasture\gdb\Contours.gdb\contours2"
fc_out = r"C:\Forum\Pasture\gdb\Contours.gdb\contour_pnts03"
fld_contour = "Contour"
interval = 3 # pick points every x meter on every contour line

# create empty output featureclass
sr = arcpy.Describe(fc_in).spatialReference
out_ws, out_name = os.path.split(fc_out)
arcpy.CreateFeatureclass_management(out_ws, out_name, "POINT", fc_in, "DISABLED", "DISABLED", sr)

# create a where clause
where = "{0} > {1}".format(arcpy.AddFieldDelimiters(fc_in, fld_contour), 1000)

# add field with contour value to output fc
arcpy.AddField_management(fc_out, fld_contour, "DOUBLE")

cnt = 0
with arcpy.da.InsertCursor(fc_out, ("SHAPE@", fld_contour)) as curs_out:
    with arcpy.da.SearchCursor(fc_in, ("SHAPE@", fld_contour), where_clause=where) as curs_in:
        for row_in in curs_in:
            polyline = row_in[0]
            contour = row_in[1]
            max_len = polyline.length
            d = 0
            while d < max_len:
                pnt = polyline.positionAlongLine(d, False)
                curs_out.insertRow((pnt.firstPoint, contour, ))
                cnt += 1
                if cnt % 100 == 0:
                    print "Processing point: {0}".format(cnt)
                # pnt.firstPoint
                d += interval
            curs_out.insertRow((polyline.lastPoint, contour, ))
            cnt += 1

Re: converting contours to points

ShahriarRahman — Sun, 01 Nov 2020 09:39:40 GMT

Hi Xander,

Can it be done for the polygons?

https://community.esri.com/thread/262214-arcpy-script-to-write-same-record-in-another-feature-layer If it can be done for polygons, then it will answer my query.

Thanks in advance.

Kind regards,

Shahriar

Re: converting contours to points

XanderBakker — Tue, 03 Nov 2020 21:12:16 GMT

Hi Shahriar Rahman

The original questions extracts points from polylines (contours), but you want to extract points from a polygon? This is possible, but how should these points be distributed? Extract points from the outline of the polygon, generate random points inside the polygon, generate points at a certain distance inside the polygon?