Latest Contributions by JoshuaBixby

Funny, I tried None, arcpy.Array(), and arcpy.Array([]); but I never thought to try arcpy.Array(None).  That said, arcpy.Polygon(arcpy.Array(None)) is a bit too baroque for my tastes.  In the context of Zen, there is nothing simple or beautiful about the current implementation.  What is problematic with arcpy.Polygon()? I will leave this idea open to push for a more elegant and straightfoward way to construct empty geometries. ... View more

OK, got it.  You are caught up in Esri semantics.  The Copy Features tool won't work for you because it copies "features from the input feature class or layer to a new feature class."  Check out the Append tool.  Although it will work with multiple input datasets, it works just fine with one input dataset. ... View more

Are you working with versioned data?  The code snippet you provide will delete all of the features in the feature classes, so it appears you are completely purging the table and repopulating it from scratch.  If you are working with versioned data, this will make your add & delete tables grow substantially.  Do you really need to replace all the records or are you trying to synchronize subsets of records between the two data sources?  Deleting all the records in an SDE table when users are consuming data from the table seems like it would lead to some strange experiences for users. ... View more

Constructing empty geometries isn't possible using the ArcPy Geometry classes. The only way to currently create an empty geometry in ArcPy is to use the arcpy.FromWKT as a geometry constructor. I propose the ArcPy Geometry classes support the construction of empty geometries. Currently, calling any of the ArcPy Geometry constructors with no arguments, a 'None' argument, or an empty arcpy.Array throws an exception. >>> arcpy.Polygon() Runtime error Traceback (most recent call last): File "<string>", line 1, in <module> File "c:\program files (x86)\arcgis\desktop10.3\arcpy\arcpy\arcobjects\mixins.py", line 222, in __init__ *gp_fixargs(args, True)) File "c:\program files (x86)\arcgis\desktop10.3\arcpy\arcpy\geoprocessing\_base.py", line 504, in <lambda> return lambda *args: val(*gp_fixargs(args, True)) RuntimeError: Object: CreateObject cannot create geometry from inputs Instead, the constructors should generate an empty geometry of the appropriate type similar to geometry constructors from other Python (Shapely) and DBMS (SQL Server) packages. >>> pg = arcpy.Polygon() >>> pg.type u'polygon' >>> pg.WKT u'MULTIPOLYGON EMPTY'     ... View more

Regarding Dan Patterson​'s suggestion, it is likely the most straightforward or simplest since it relies on using built-in list methods and slicing, but there are still some things you should think about. One, can the second-maximum item be the same as the maximum? >>> a = [5, 3, 5, 4, 1, 2] >>> a.sort() >>> a[-1] 5 >>> a[-2] 5 If not, collapsing the list into a set is one way to address the issue. >>> a = [5, 3, 5, 4, 1, 2] >>> a = list(set(a)) >>> a.sort() >>> a[-1] 5 >>> a[-2] 4 Second, sorting lists in Python is generally O(n log n) while getting max or min is O(n) (TimeComplexity - Python Wiki) .  If you are working with large lists, especially extremely large ones, the overhead of sorting the list to find the second highest maximum won't be trivial.  If you are working with large lists and performance matters, there is a good discussion thread over at stackoverflow on finding the second largest value:  Get the second largest number in a list in linear time. ... View more

Dan Patterson​, regarding syntax highlighting in blog comments, it is a hassle because the Advanced Editor isn't available.  I typically compose my blog comments in a draft discussion post and then copy and paste the raw HTML into the blog comment.  Annoying but gets the job done. ... View more

I agree.  I had some thoughts in my head on this subject, and your blog post was the nudge I needed to get them written down. Whether a bug or design failure, I think something is remiss with the ArcPy Geometry Classes when it comes to constructing geometries.  If Esri wants to claim that Point is not a geometry class so it can't support an empty point, fine, but then arcpy.Point() and arcpy.Point(None) should throw exceptions instead of returning POINT (0 0).  Additionally, PointGeometry should support calling with no arguments or a None argument to generate an empty point instead of throwing exceptions the way it does now. Just for fun, it is interesting to see how Shapely handles this situation: >>> from shapely.geometry import Point >>> point_empty = Point() >>> type(point_empty) <class 'shapely.geometry.point.Point'> >>> point_empty.wkt 'GEOMETRYCOLLECTION EMPTY' With Shapely, the Point object is actually a geometry class, unlike with ArcPy.  Also, calling Point with no arguments returns an empty point as an empty geometry collection. ... View more

I don't mean to get hung up on semantics, but I usually can't help myself.  Are you interested in a null point or empty point?  Without getting into the debate of whether Python has a null or not, isn't the Python equivalent of a null anything None? Even when a company like Esri, Microsoft, Oracle, or [insert open source product here] says they are implementing the OGC Simple Feature standards (Simple Feature Access - Part 1: Common Architecture, Simple Feature Access - Part 2: SQL Option, etc...), I have come to expect idiosyncrasies when it comes to how those standards are implemented or translate to a company's geometry data type. When it comes to Esri, specifically ArcPy, it took me a while to figure out that they do in fact implement an empty point or POINT EMPTY.  My initial confusion came from not appreciating what I was reading in Esri's documentation:  Point -- Help | ArcGIS for Desktop. Discussion A Point is not a geometry class, but is commonly used to construct geometry. In the example below, a Point is used to create a PointGeometry object. It is a bit odd that Esri puts the Point documentation in with the geometry classes, but the documentation itself does clearly state that a Point is not a geometry class.  Typing the objects in Python does affirm what the documentation states: >>> point = arcpy.Point() >>> type(point) <class 'arcpy.arcobjects.arcobjects.Point'> >>> pointGeometry = arcpy.PointGeometry(point) >>> type(pointGeometry) <class 'arcpy.arcobjects.geometries.PointGeometry'> It is at this point that I have to start assuming what Esri was thinking because I have yet to find any documentation that explains the following. Since Point is not a geometry class, it cannot implement an empty point, or at least it doesn't.  Instead, an empty point is implemented in PointGeometry.  Where things are really awkward is that PointGeometry as a point geometry constructor requires either Point or Array objects.  If Point can't construct an empty point, how does one go about making PointGeometry construct an empty point?  Maybe pass an empty Array object or an Array object with a None object? >>> point <Point (0.0, 0.0, #, #)> >>> pointGeometry.WKT u'POINT (0 0)' >>> pointGeometry = arcpy.PointGeometry(arcpy.Array()) Runtime error Traceback (most recent call last):     .... RuntimeError: Object: CreateObject cannot create geometry from inputs >>> pointGeometry = arcpy.PointGeometry(arcpy.Array(None)) Runtime error Traceback (most recent call last):     .... RuntimeError: Object: CreateObject cannot create geometry from inputs Nope, that doesn't work.  Fortunately, there are other geometry constructors.  My preference is to use arcpy.FromWKT (FromWKT -- Help | ArcGIS for Desktop). >>> pointGeometry = arcpy.FromWKT('POINT EMPTY') >>> pointGeometry.WKT u'POINT EMPTY' >>> pointGeometry.JSON u'{"x":"NaN","y":"NaN","spatialReference":{"wkid":null}}' >>> repr(pointGeometry.firstPoint) 'None' If the Point associated with an empty point is really of NoneType instead of arcpy.arcobjects.arcobjects.Point, can we pass a None object to PointGeometry to create an empty point? >>> arcpy.PointGeometry(None) Runtime error Traceback (most recent call last):     .... RuntimeError: Object: CreateObject cannot create geometry from inputs Again, no.  The question now, or at least when I first reached this point, is whether ArcGIS and ArcPy actually implement an empty point or whether the empty point from using arcpy.FromWKT just looks like an empty point.  I can't say I have done exhausting testing, but a few cursory checks indicate it isn't just appearances. >>> point_empty = arcpy.FromWKT('POINT EMPTY') >>> point_empty.WKT u'POINT EMPTY' >>> point = arcpy.FromWKT('POINT (1 1)') >>> point.WKT u'POINT (1 1)' >>> #Check that union of point with empty point is point >>> point.union(point_empty).WKT u'MULTIPOINT ((1 1))' >>> #Check that intersect of point with empty point is empty point >>> point.intersect(point_empty, 1).WKT u'POINT EMPTY' >>> #Check that point contains empty point >>> point.contains(point_empty) True >>> #Check that point is disjoint from empty point >>> point.disjoint(point_empty) True In the end, it seems ArcGIS and ArcPy implement an empty point, but the ArcPy Geometry Classes fail as constructors to support it. ... View more

So running the script you posted is noticeably slower than doing it manually?  Creating the versions is quicker if you do it one by one manually? ... View more

You had this exact workflow working on this exact machine using an earlier version?  What version? ... View more

Shaun Walbridge​, good news, indeed. With Pro having its own numbering/versioning scheme, separate from ArcGIS Desktop, it gets a bit confusing in terms of what will be released when.  Outside of ArcGIS 10.3.1 being released shortly, is release information for ArcGIS Desktop 10.3.2, ArcGIS 10.4, and ArcGIS Pro 1.1 publicly documented anywhere? ... View more

Interesting, I guess I never noticed.  Now the lack of datetime support with ArcGIS and NumPy hurts even more. ... View more

Typically, I use an SDE connection file to a regular/nonSDE database for simplicity's sake, but the connection can be created on the fly.  Here is a generalized example for SQL Server Express: sde_conn = arcpy.ArcSDESQLExecute(instance="sde:sqlserver:host\MSSQLExpress", database="DB") The above will use Operating System Authentication since I am connecting to SQL Server and not specifying a username/password. The syntax for creating on-the-fly connections using ArcSDESQLExecute is the same as the direct connect syntax prior to ArcGIS 10.1 when they started changing connections to databases. ... View more