Latest Contributions by Zeke

You want to use InsertLayer. Give that a try and post back with any problems you have. ... View more

Thanks. If I understand correctly (always questionable), I think that's the direction I'm going. Not a finished product below, but where I'm heading... import arcpy import pythonaddins lstChanged = [] fc = r"C:\path\to\layer\Lots" field = "OBJECTID" class CheckSelectionChange(object):     """Implementation for PyAddInWizard_addin.ext1 (Extension)"""     def __init__(self):         # For performance considerations, please remove all unused methods in this class.         self.enabled = True     def onEditorSelectionChanged(self):         fc = r"C:\Users\gkeith\Documents\Projects\Laurie\LaurieTest.gdb\Lots"         field = "OBJECTID"         with arcpy.SearchCursor(fc, field) as row:             if row.field in lstChanged:                 lstChanged.pop(row.field)    # this may be unnecessary, but will try it             else:                 lstChanged.append(row.field) class CreateLotNum(object):     """Implementation for PyAddInWizard_addin.btn1 (Button)"""     def __init__(self):         self.enabled = True         self.checked = False     def onClick(self): # button event handler         lstDoubleCheck = []         with arcpy.SearchCursor(fc, field) as row:             lstDoubleCheck.append(row.field)     # plan to check lstDoubleCheck, all currently selected parcels, against lstChanged, any that were listed in onEditor... ... View more

At a guess, I'd say that you don't have your paths set up correctly. That's what the error for line 1, import sys suggests. Python can't find the sys module. ... View more

Thanks Wayne, you're correct. Listen for selection change, determine if the item is selected or deselected, and add or drop it from the list respectively. It's trivial to number at that point, but getting to that point is the problem. There's a tool in the parcel fabric and/or local government model that does something similar when drawing a line through the lots, but we're not there yet. I also need to allow the user to set the starting number. Python add-in extensions have an event onEditorSelectionChanged(self), but I can't find any documentation on how to use it properly.What I really need is a property like isSelected I could check. One option might be to forget selection and create two buttons, a start and a stop, with each click after start incrementing by one until the user clicks stop. Not sure if I can hijack the cursor to do that though. I'll take a look at your method. Thanks again. ... View more

Not sure this will work, but look into Create Fishnet. This can create lines that you could use to split the polygon. Part I'm not sure of is how to guarantee 730 cells. You might be able to divide the area of the polygon by 730 to get cell height & width, but if the fishnet is created on the extent of the polygon rather than the feature itself this might not work. ... View more

Other options include PyScripter (my favorite), Notepad ++, ConText, etc. ... View more

Are these individual points or a multi-point feature? If multi-point, explode them first. If you have them selected in an edit session, the Delete key should get rid of them, no need to clip. Clipping would require a separate shapefile for the clipping feature. ... View more

It might be easier to georeference the tif to the points. Not familiar with the British National Grid, but it sounds like although you may have projected the points, their values are still in their original system (GCS?).  So if your coordinates are 51.5 N 0.4 W, your point will be 51.5 meters N, 0.4 meters W of whatever the origin point is for the BNG (assuming its unit is meters). If all your points seem bunched up into a small area, this is most likely the cause. Did you define a projection as well as project the points? One quick fix that may work is to create a feature dataset in a file gdb, set its coordinate system to BNG, and import your points into that. ... View more

You can also do a slow double click on the layer name in the TOC so that the name is highlighted in a box and enter a new name, similar to renaming a file in Windows Explorer. You can also change the symbology labels under the Label heading on the Symbology tab. You could change the actual name of the shapefile or feature class, but that will break existing links in the map. You can reset those, of course. ... View more

Well, then in your loop you might want to first build a list of the non-zero values and calculate on those. Here's a very untested quick conceptual method. Think of it as pseudo-code. for row in rows:     validlist = []     if row.A <> 0: validlist.append(row.A) # trying to think of a way to loop this part, drawing a blank     if row.B <> 0: validlist.append(row.B)     if row.C <> 0: validlist.append(row.C)     .     .     .     if row.N <> 0: validlist.append(row.N)         result = validlist[0] * Ln(1/validlist[0])     for i in range(1, len(validlist) + 1):         result += validlist * Ln(1/validlist)                 ... View more

Thanks both! ... View more

Two methods, depending on whether you want to skip the calculation altogether if any value is zero, or if you want to calculate any non-zero values, skipping only zeros. If you have a lot of values to calculate, there's probably a better way, but this will work for your example. edit: also, you marked your own post as answered (green check mark). Use that for whoever best answered your question. Other forum members may not read your post, assuming it's been solved. # Method 1 for row in rows:     if A == 0 or B == 0 or C == 0:    # you may actually want row.A, etc, here, or row[0], row[1]. Second method is if you use arcpy.da         continue    # this will skip this row in the for loop     else:         # do your calculations # Method 2 for row in rows:     if A == 0 and B != 0 and C != 0:         # calculate only B and C     elif A != 0 and B != 0 and C == 0:         # calculate only A and B     elif: # and so on, for as many combinations as you have ... View more