Add a field to multiple feature classes

Adding a Field to Multiple Feature Classes: A Guide for Real People

Let’s face it, in the GIS world, time is money. We’ve all been there: staring at a mountain of spatial data, realizing we need to tweak the structure. A common task? Adding a new field (or column, as some call it) to the attribute table of multiple feature classes. Sounds tedious, right? It can be, but it doesn’t have to be. This guide is all about making that process smoother, saving you precious time and brainpower.

Feature Classes and Attribute Tables: A Quick Refresher

Okay, before we dive in, let’s quickly level-set. Think of a feature class as a container for geographic goodies – points, lines, polygons, you name it. What ties them together? They all have the same type of geometry and the same fields in their attribute tables. And that attribute table? It’s like a spreadsheet linked to your map, storing all the juicy details about each feature i. Each row is a feature, and each column? That’s an attribute, or a field, holding information like names, IDs, or measurements i.

Why Bother Adding Fields Anyway?

So, why would you even want to add a field to a bunch of feature classes? Turns out, there are plenty of good reasons:

• Getting Everyone on the Same Page: Sometimes, you just need to standardize your data. Adding a common attribute to several feature classes ensures everything speaks the same language i.
• Number Crunching: Need to calculate something new based on existing data? A new field is the perfect place to store those results, like converting square feet to square meters i.
• Mixing and Matching Data: Ever tried to combine data from different sources only to find they don’t quite match up? Adding a field can help bridge the gap and make everything play nicely together i.
• Sorting Things Out: Sometimes you need to categorize your features. A new field can be the perfect way to tag them based on specific criteria i.

Let’s Get Practical: Adding Fields in ArcGIS and QGIS

Alright, enough theory. Let’s get our hands dirty. The exact steps depend on your GIS software of choice, so we’ll cover both ArcGIS and QGIS.

ArcGIS: The Swiss Army Knife of GIS

ArcGIS offers a few different ways to tackle this task:

1. The Add Field Tool: Batch Processing Power

The “Add Field” tool is your go-to for simple field additions i. But the real magic happens when you use it in batch mode. This lets you add the same field to multiple feature classes all at once i! Here’s the lowdown:

2. Calculate Fields Tool: More Than Just Calculations

Don’t let the name fool you. The “Calculate Fields” tool can also be used in batch to add a new field and calculate values for it, all in one go i.

3. Python Scripting: Unleash Your Inner Coder

For those who like a bit more control (or have a lot of feature classes to process), Python scripting with ArcPy is the way to go i. It’s like giving ArcGIS a set of very specific instructions.

Here’s a taste of what that looks like:

python