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Python "attribute information tool for xy location" HELP! IM A BEGINNER!

ChristiNelson1

A co-worker of mine has a couple of web applications that need to call a Geoprocessing Tool.

The tool creation has been assigned to me - but I am a novice Python programmer. The tool is supposed to act like the 'i' (identify) button on ArcGIS desktop, but instead of returning info about one feature class, it needs to return only one specific attriburte from many feature classes.

Specifically, it should return city, county, basemap and other feature layer information for a given coordinate. She has requested such a function be created by using Python in ArcMap. The input values are: cooidinate_east, cooidinate_north. The output values are: city_name, county_nm, bmap_code.

Is this possible? Suggestions?
Christi

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MathewCoyle

As I said before this line seems to be the culprit.

if layer.name.lower() == "BND_GDT_CNTY":

Nothing after that will process. You will want to replace .lower with .upper as I posted above.

ChristiNelson1

I am unable to upload attachments, for some reason its telling me they are too large (3200 kb). Oh well. It was just an mxd with a feature class in it, plus the .gdb that contained it. Also included was the python script (indented below):

#import modules
import arcpy, os, tempfile
arcpy.env.overwriteOutput = 1

#Create workspace
arcpy.env.workspace = r"H:\Projects\LocationDetector\Scratch.gdb"





#Create a Point Object from coordinates
point = arcpy.Point(6088757.617, 2077662.44)

#Print point properties to make sure entered correctly
print("Point properties:")
print(" ID: {0}".format(point.ID))
print(" X:  {0}".format(point.X))
print(" Y:  {0}".format(point.Y))


#Create Point Geometry object using Spatial Reference Factory Code
ptGeometry = arcpy.PointGeometry(point, 2227)

#Create a copy ofthe point geometry object by using ptGeometry as input to the CopyFeatures tool
arcpy.CopyFeatures_management(ptGeometry, r"H:\Projects\LocationDetector\Scratch.gdb\POINT")

#Use the POINT feature and create a feature layer called "point_lyr"                           
arcpy.MakeFeatureLayer_management(r"H:\Projects\LocationDetector\Scratch.gdb\POINT", "point_lyr")



###Create table to write coordinates into.  Make sure file doesn't already exist.  If it does, remove file. 
##logpath = r"H:\Projects\LocationDetector\file.txt"
##if os.path.exists(logpath):
##    os.remove(logpath)
##
###create variable to open .txt file with write access.
##f = open(logpath, "w")

##go to .mxd and first dataframe.  
mxd = arcpy.mapping.MapDocument(r"H:\Projects\LocationDetector\LDtest3.mxd")
df = arcpy.mapping.ListDataFrames(mxd)[0]

#list layers in dataframe, go to counties layer and make it a feature layer.
#select dataframe feature layer by location using point feature layer ("point_lyr" created above from coordinates)
for layer in arcpy.mapping.ListLayers(mxd, '', df):
    print(layer)
    if layer.name.lower() == "BND_GDT_CNTY":
        arcpy.MakeFeatureLayer_management(layer, "counties_lyr")
        arcpy.SelectLayerByLocation_management("counties_lyr", "INTERSECT", "point_lyr", "30 FEET", "NEW_SELECTION")
        rows = arcpy.da.SearchCursor("counties_lyr", "", "", "NAME")

        currentState = ""
#Iterate thru the rows in the cursor
        for row in rows:
            if currentState != row.NAME:
                currentState = row.NAME
#Print out the county name
            print "County: %s" % \
                  (row.NAME)
            
##            print(row.NAME)
##            f.write(row.NAME)
            
        del row, rows


##f.close()
arcpy.Delete_management(r"H:\Projects\LocationDetector\Scratch.gdb\POINT")

MathewCoyle

Hi all,

I've had to change the script to just accept coordinates that are written into a .py script. The programmer doesn't want a tool - just a script that has been tested successfully for a set of coordinates to retrieve attribute values for that point. So I've changed the script to the following. The commented out code is potential code for writing the output values to a .txt file, but for now I jsut want the values printed in the PythonWin Interactive Window, so that I can see what I'm getting. My code seems to be stuck at "for layer in arcpy.mapping.ListLayers(mxd, '', df):
print(layer)".

It prints the layers into the Interactive Window and then gives me a message ".py returned exit code 0". Nothing else processes after this step and I don't get any error messages to help me. Attached is a .zip with a .gdb, .py and .mxd.

Suggestions?

I think you forgot to attach your files. Also to post code in the forums use [ CODE] [/ CODE] tags.

At a cursory inspection this line will never return anything.

if layer.name.lower() == "BND_GDT_CNTY":

You'll want this I believe.

if layer.name.upper() == "BND_GDT_CNTY":

ChristiNelson1

Hi all,

I've had to change the script to just accept coordinates that are written into a .py script. The programmer doesn't want a tool - just a script that has been tested successfully for a set of coordinates to retrieve attribute values for that point. So I've changed the script to the following. The commented out code is potential code for writing the output values to a .txt file, but for now I jsut want the values printed in the PythonWin Interactive Window, so that I can see what I'm getting. My code seems to be stuck at "for layer in arcpy.mapping.ListLayers(mxd, '', df):
    print(layer)".

It prints the layers into the Interactive Window and then gives me a message ".py returned exit code 0". Nothing else processes after this step and I don't get any error messages to help me. Attached is a .zip with a .gdb, .py and .mxd.

Suggestions?

#import modules
import arcpy, os, tempfile
arcpy.env.overwriteOutput = 1

#Create workspace
arcpy.env.workspace = r"H:\Projects\LocationDetector\Scratch.gdb"

#Create a Point Object from coordinates
point = arcpy.Point(6088757.617, 2077662.44)

#Print point properties to make sure entered correctly
print("Point properties:")
print(" ID: {0}".format(point.ID))
print(" X: {0}".format(point.X))
print(" Y: {0}".format(point.Y))

#Create Point Geometry object using Spatial Reference Factory Code
ptGeometry = arcpy.PointGeometry(point, 2227)

#Create a copy ofthe point geometry object by using ptGeometry as input to the CopyFeatures tool
arcpy.CopyFeatures_management(ptGeometry, r"H:\Projects\LocationDetector\Scratch.gdb\POINT")

#Use the POINT feature and create a feature layer called "point_lyr"
arcpy.MakeFeatureLayer_management(r"H:\Projects\LocationDetector\Scratch.gdb\POINT", "point_lyr")

###Create table to write coordinates into. Make sure file doesn't already exist. If it does, remove file.
##logpath = r"H:\Projects\LocationDetector\file.txt"
##if os.path.exists(logpath):
##    os.remove(logpath)
##
###create variable to open .txt file with write access.
##f = open(logpath, "w")

##go to .mxd and first dataframe.
mxd = arcpy.mapping.MapDocument(r"H:\Projects\LocationDetector\LDtest3.mxd")
df = arcpy.mapping.ListDataFrames(mxd)[0]

#list layers in dataframe, go to counties layer and make it a feature layer.
#select dataframe feature layer by location using point feature layer ("point_lyr" created above from coordinates)
for layer in arcpy.mapping.ListLayers(mxd, '', df):
    print(layer)
    if layer.name.lower() == "BND_GDT_CNTY":
        arcpy.MakeFeatureLayer_management(layer, "counties_lyr")
        arcpy.SelectLayerByLocation_management("counties_lyr", "INTERSECT", "point_lyr", "30 FEET", "NEW_SELECTION")
        rows = arcpy.da.SearchCursor("counties_lyr", "", "", "NAME")

        currentState = ""
#Iterate thru the rows in the cursor
        for row in rows:
            if currentState != row.NAME:
                currentState = row.NAME
#Print out the county name
            print "County: %s" % \
                  (row.NAME)

##            print(row.NAME)
##            f.write(row.NAME)

        del row, rows

##f.close()
arcpy.Delete_management(r"H:\Projects\LocationDetector\Scratch.gdb\POINT")

MathewCoyle

Hi there,

I have a question about this part of the code: if layer.name.lower() == "cities":

why do you put ".name.lower()" what does .lower mean? The lowest layer in the dataframe toc? Is it necessary to write this? I will have more than one layer in mine..

Thanks for clarifying.
Christi

It is so it can pick whatever layer is called "cities" regardless of capitalization. So it would return "Cities", "CITIES", "cities" etc.

ChristiNelson1

Hi there,

I have a question about this part of the code: if layer.name.lower() == "cities":

why do you put ".name.lower()" what does .lower mean? The lowest layer in the dataframe toc? Is it necessary to write this? I will have more than one layer in mine..

Thanks for clarifying.
Christi

jskinner

You can easily write the output to a text file. Take a look at the examples here. Also, here is an updated example of the script posted earlier:

logpath = r"C:\temp\python\file.txt"
if os.path.exists(logpath):
    os.remove(logpath)

f = open(logpath, "w")

mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]
for layer in arcpy.mapping.ListLayers(mxd, '', df):
    if layer.name.lower() == "cities":
        arcpy.MakeFeatureLayer_management(layer, "cities_lyr")
        arcpy.SelectLayerByLocation_management("cities_lyr", "INTERSECT", "point", "30 FEET", "NEW_SELECTION")
        rows = arcpy.SearchCursor("cities_lyr")
        for row in rows:
            f.write(row.NAME)
        del row, rows

f.close()

Note: Be sure to import the 'os' module if you are going to check if the file already exists.

ChristiNelson1

Happy Friday!

Im thinking that rather than putting the results in the python window, I may need to write them to a text file or table of some sort. This may be easier for a programmer to call the results into a pop up window.

Thoughts?

jskinner

In the above example, the script creates a shapefile and then removes it at the end using the 'arcpy.Delete_management' function. However, you can create an IN_MEMORY feature class. This is a temporary feature class. You would need to update the following lines:

arcpy.CopyFeatures_management(ptGeometry, r"C:\temp\python\POINT.shp")

arcpy.MakeFeatureLayer_management(r"C:\temp\python\POINT.shp", "point")

to:

arcpy.CopyFeatures_management(ptGeometry, "IN_MEMORY/POINT")

arcpy.MakeFeatureLayer_management("IN_MEMORY/POINT", "point")

The reason I used a shapefile was the problem with the bug mentioned before. At 10.0, using an IN_MEMORY feature class should work. More information about IN_MEMORY feature classes can be found here.

ChristiNelson1

First off, I want to say thank you for all of your help. This has been a very positive and encouraging experience for me using Python. 🙂

I do have a question about the final code sample. Will this end up creating a bunch of new shapefiles (or feature classes) and layer files in the geodatabase, or are these somehow temporary and go away at the end of the process?

What to do if they don't go away? I imagine users will be randomly wanting information from a variety of locations...

Cheers and thanks again,
Christi

ChristiNelson1

I was able to get this working if I wrote the PointGeometry to a shapefile rather than an IN_MEMORY feature, or a feature class. Here's an example:
import arcpy
arcpy.env.overwriteOutput = 1
input = arcpy.GetParameterAsText(0)

rows = arcpy.SearchCursor(input)
for row in rows:
    geom = row.shape
    X = geom.centroid.X
    Y = geom.centroid.Y

point = arcpy.Point(X, Y)
ptGeometry = arcpy.PointGeometry(point)

arcpy.CopyFeatures_management(ptGeometry, r"C:\temp\python\POINT.shp")

arcpy.MakeFeatureLayer_management(r"C:\temp\python\POINT.shp", "point")

mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]
for layer in arcpy.mapping.ListLayers(mxd, '', df):
    if layer.name.lower() == "cities":
        arcpy.MakeFeatureLayer_management(layer, "cities_lyr")
        arcpy.SelectLayerByLocation_management("cities_lyr", "INTERSECT", "point", "30 FEET", "NEW_SELECTION")
        rows = arcpy.SearchCursor("cities_lyr")
        for row in rows:
            arcpy.AddMessage(row.NAME)
            print row.NAME
        del row, rows

arcpy.Delete_management(r"C:\temp\python\POINT.shp")
You can add more 'if' statements for the other layers you would like to identify, and alter the 'arcpy.AddMessage' to display the info you would like to show. The info will be reported to the GP windows, or to the 'Results' window > Messages. I couldn't find a way to display the info to the Python window at 10.0, but this works using an add-in at 10.1.

Also, I believe since I used a shapefile the XY coordinates were slightly different when trying to identify a point feature class. I had to adjust the search distance to around 30 feet in the Select Layer by Location function to identify the correct point (city in the above example).

I missed this post some how! I will test ths out now. Thank you!

jskinner

Take a look at my previous example. Instead of writing the output to a shapefile you can easily write it to a feature class instead.

ChristiNelson1

Hmmm. Now how do i bring this back into the tool to get the tool to work? Im getting an error:

>>> import arcpy, os, tempfile
... import win32clipboard as w
... ##import win32con
...
... input = arcpy.GetParameterAsText(0)
...
... temp_table = tempfile.mktemp(suffix='.txt')
...
... output = open(temp_table, "w")
...
... cur = arcpy.SearchCursor(input)
...
... for row in cur:
... geom = row.Shape
... X = geom.centroid.X
... Y = geom.centroid.Y
... output.write(XY)
...
... ##output.close()
...
... output = open(temp_table, "r")
... XY = output.read()
... pointList = [XY]
... point = arcpy.Point()
... pointGeometryList = []
... for pt in pointList:
... point.X = pt[0]
... point.Y = pt[1]
... pointGeometry = arcpy.PointGeometry(point)
... pointGeometryList.append(pointGeometry)
... arcpy.CopyFeatures_management(pointGeometryList, "H:\Projects\LocationDetector\Test.gdb\points")
...
Runtime error <type 'exceptions.RuntimeError'>: Point: Input value is not numeric

jskinner

Glad you got it to work! I originally tested this with 10.1, but could not get it working. I tried 10.0 and it worked. This may be a bug with 10.1.

ChristiNelson1

Got it to work: for even a single set of coords, set up a pointlist (replace with your own coords and path)... How do I attach this correctly to the previous code and then use as a variable?

pointList = [[6044782.84206, 2142068.46912]]
point = arcpy.Point()
pointGeometryList = []
for pt in pointList:
     point.X = pt[0]
     point.Y = pt[1]
     pointGeometry = arcpy.PointGeometry(point)
     pointGeometryList.append(pointGeometry)
arcpy.CopyFeatures_management(pointGeometryList, "H:\Projects\LocationDetector\Test.gdb\points")

jskinner

I was able to get this working if I wrote the PointGeometry to a shapefile rather than an IN_MEMORY feature, or a feature class. Here's an example:

import arcpy
arcpy.env.overwriteOutput = 1
input = arcpy.GetParameterAsText(0)

rows = arcpy.SearchCursor(input)
for row in rows:
    geom = row.shape
    X = geom.centroid.X
    Y = geom.centroid.Y

point = arcpy.Point(X, Y)
ptGeometry = arcpy.PointGeometry(point)

arcpy.CopyFeatures_management(ptGeometry, r"C:\temp\python\POINT.shp")

arcpy.MakeFeatureLayer_management(r"C:\temp\python\POINT.shp", "point")

mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]
for layer in arcpy.mapping.ListLayers(mxd, '', df):
    if layer.name.lower() == "cities":
        arcpy.MakeFeatureLayer_management(layer, "cities_lyr")
        arcpy.SelectLayerByLocation_management("cities_lyr", "INTERSECT", "point", "30 FEET", "NEW_SELECTION")
        rows = arcpy.SearchCursor("cities_lyr")
        for row in rows:
            arcpy.AddMessage(row.NAME)
            print row.NAME
        del row, rows

arcpy.Delete_management(r"C:\temp\python\POINT.shp")

You can add more 'if' statements for the other layers you would like to identify, and alter the 'arcpy.AddMessage' to display the info you would like to show. The info will be reported to the GP windows, or to the 'Results' window > Messages. I couldn't find a way to display the info to the Python window at 10.0, but this works using an add-in at 10.1.

Also, I believe since I used a shapefile the XY coordinates were slightly different when trying to identify a point feature class. I had to adjust the search distance to around 30 feet in the Select Layer by Location function to identify the correct point (city in the above example).

jskinner

That's actually a script that I wrote a while ago that I'm trying to modify. I'm trying to alter the XY coordinates and create a point geometry from them. Ex:

point = arcpy.Point(-88.24873, 34.232039)
ptGeometry = arcpy.PointGeometry(point)

arcpy.CopyFeatures_management(ptGeometry, "c:/temp/python/test.gdb/points")

However, the output is empty. If I add two sets of points, it works:

pointList = [[-88.24873, 34.232039], [-77.99395, 34.232196]]
point = arcpy.Point()

pointGeometryList = []

for pt in pointList:
    point.X = pt[0]
    point.Y = pt[1]

    pointGeometry = arcpy.PointGeometry(point)
    pointGeometryList.append(pointGeometry)

arcpy.CopyFeatures_management(pointGeometryList, "c:/temp/python/test.gdb/points")

I'm trying to figure out why I cannot create a PointGeometry with a single point.

ChristiNelson1

I found a great script below to get me started on getting XY from a click, but I need help with modifying.

This script is set up as a Feature Set type of tool input. So it allows user to interactively click on screen to get a temporary point location. It copies the coordinates to temp table, where the output is copied to a clipboard.

Im wondering, instead of copying XY coords to the clipboard, how I can get them to be given as an output that can be used an input variable for my next tool.... Can someone help modify? Code is below. The tool sample (script and toolbox) can be downloaded here:
http://resources.arcgis.com/gallery/file/geoprocessing/details?entryID=0BF2E736-1422-2418-3416-5AA910449F6E

import arcpy, os, tempfile
import win32clipboard as w
##import win32con

input = arcpy.GetParameterAsText(0)

temp_table = tempfile.mktemp(suffix='.txt')

output = open(temp_table, "w")

cur = arcpy.SearchCursor(input)

for row in cur:
    geom = row.Shape
    X = geom.centroid.X
    Y = geom.centroid.Y
    output.write(str(X) + " " + str(Y) + " ")

##output.close()

output = open(temp_table, "r")
XY = output.read()
##FROM HERE IS WHERE I NEED ADVICE ON HOW TO GET XY AS A VARIABLE FOR AN INPUT PARAMETER TO MY NEXT TOOL##
w.OpenClipboard()
w.EmptyClipboard()
w.SetClipboardData(w.CF_TEXT, XY)
w.CloseClipboard()

XY Cursor.py.zip

ChristiNelson1

Hi,

Im in 10.0. I think for now, just writing it to the python window and then being able to use the coordinates as input to be able to select the intersecting layers in the .mxd would be the best bet. I just don't know how to do that.

I think another programmer could then call this information/tool and bring it into javascript or other code for a pop-up.

Thoughts?

jskinner

Hi Christi,

Are you using ArcGIS 10 or 10.1?

The difficult part would be creating the output dialog box that mimics the identify tool's dialog box. You could easily write the information to the python window, but I'm not sure if that would work for you.

ChristiNelson1

Any ideas about how to get those xy coordinates from the 'click' into the rest of the process?

ChristiNelson1

For instance, do you need that output into a table or a text file or associated with a point feature class (where the points are your input coordinates), or does this need to be something that feeds another process as in a web application? How do you do you plan to supply the coordinates at which you need the information - user input into a form? a mouse click in a map? from a point shapefile that is created in advance? Those kind of interactions (input and output) can greatly influence all the particulars between. If you can help with those details that will help direct the feedback get.

So, the user will click on the map to get the XY coordinates. Those coordinates will then be used as the input. Output will be a window that looks similar to the widow that the identify tool displays in ArcMap (but it will only show a specific record from each feature class).

Hope that helps,
Christi

ChristopherThompson

Arcadius' suggestions are probably the right direction, but there are other things you need to handle to. For instance, what do you need as some sort of 'output' from the tool? For instance, do you need that output into a table or a text file or associated with a point feature class (where the points are your input coordinates), or does this need to be something that feeds another process as in a web application? How do you do you plan to supply the coordinates at which you need the information - user input into a form? a mouse click in a map? from a point shapefile that is created in advance? Those kind of interactions (input and output) can greatly influence all the particulars between. If you can help with those details that will help direct the feedback get.

ArkadiuszMatoszka

You can create geometry from coordinates:
http://resources.arcgis.com/en/help/main/10.1/index.html#//018z0000006t000000

Than use arcpy.SelectLayerByLocation_management to select feature layers:

http://resources.arcgis.com/en/help/main/10.1/index.html#/Select_Layer_By_Location/001700000072000000/

And search cursor to extract values.

Maybe someone will have better idea, but that should do.

Hope it will help.

Cheers.

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