Overlay Toolset–Full Functionality using and ArcView License

Within ArcInfo the Overlay toolset contains  a rich set of tools i.e. Erase, Identity, Intersect, Spatial Join, Symmetrical Difference, Union, and Update.  But if you only have an ArcView license (aka the majority of GISers out there) then you only get Intersect (two inputs only), Union (two inputs only), and Spatial Join.

So what do you do if you only have ArcView?  Well thankfully it isn’t very difficult to use the already existing capabilities of ArcGIS and a little bit of Python programming to roll your own.

Intersect and Union are the easiest ones to overcome, all you need to do is know how to split a multi-value list and loop over the results (yeah you might not be able to use the ranks option…but how many people actually use that and don’t have AI already).

Then all you need to do is get back to basics.  For example, a symmetric difference is essentially a UNION minus an INTERSECT.  Erase is a little trickier but still doable via some additional select by’s and some light post processing.

Identity, well the tricky part here is the “keep relationships” option.  Personally I never use that option because of the way the attributes get renamed.  So with this one simplifying step an identity can be created chaining the existing tools and again some minor post processing.

Update is an interesting one but still relatively straightforward – often wondered why this one existed in the first place since it is remarkably similar (but not exactly the same) as an erase and append.

Anyways, in the span of a morning we were able to write the full suite of Overlay tools so that even at an ArcView license level you can get a reasonable hand drawn facsimile of the functionality available with ArcInfo.

if you too would like these and other tools available and would like to learn how to make these tools yourself then sign up for the Advanced version of our Geoprocessing with Python course via BrainCandiii.

Features toolset … Progress

Continuing from the last post — nice progress this week made on a the AI only tools in the Features Toolset.  This is turning out to be super useful!  

Yesterday we knocked out another 5 tools from the Data Management Toolbox that were limited or non-existent in ArcView and ArcEditor, ahem, ArcGIS for Desktop Basic and ArcGIS for Desktop Professional.  While we were at it we added in some additional functionality to the tools, you know, just to increase the number of pieces of flair.

Squashing AI Only Tools

When I first cut my teeth in GIS I was introduced at the ArcView GIS 3.x days but after some time learned about Arc/Info Workstation.  Ever since then I’ve been conscious of the differences in functionality between the products and even more so since everything was blended together in ArcGIS Desktop.

Although most of us in the company usually use AI (Professional for those early adopters of 10.1) for our normal work, our development mantra has been to assume nothing and code for AV wherever possible.  Of course this is not so much of a hard/fast rule as it is just guidance and practice so sometimes we forget that most people do not have AI (Professional) and oops!, in slips an AI only tool.  Of course there are some other tools that just act differently when not using AI, for example, union and intersect only allow for two inputs.  We lump these into the same category as AI only since we really want the same behavior in our code.

Something we have chatted about internally for some time now has been writing some reasonably hand drawn facsimiles of the the AI only tools and including them inside of pygp.  Not necessarily exposing new toolboxes or tool interfaces just so that when an AI only tool is called from within our code base that the license level is checked and if AI is not available then use the alternative code.

Easy enough to identify the tools that need to be addressed – this is published – and even easier to identify those that should be addressed first (i.e. the ones we bump up against the most often).

Today seemed like as good a day as any to start cracking on this idea.  Churned out three tools from the Analysis toolbox and have stubbed out the code for five more from the Data Management toolbox.  Should make for a very sidebar project to start the year off right.