Generating tessellation in ArcGIS Desktop versions before 10.3

Making Grids Before ArcGIS Got Fancy: Tessellations in Older ArcGIS Desktop

So, you’re stuck using an older version of ArcGIS Desktop – maybe pre-10.3? Don’t sweat it! Just because you don’t have the fancy “Generate Tessellation” tool doesn’t mean you can’t create those cool tessellated grids. In fact, getting creative with older software can be kind of fun. Let’s dive into how to make it happen.

Why Bother with Tessellations Anyway?

Tessellations, at their heart, are just ways of dividing up space into repeating shapes. Think of them as tiling your bathroom floor, but in GIS. Why would you want to do this? Well, they’re super handy for all sorts of analysis. For example, imagine you want to see where crime is most concentrated in a city. You could overlay a grid and count the number of incidents in each cell. Or, if you’re planning a field survey, a grid helps you collect data systematically. They’re also great for visualizing data – a uniform grid gives you a consistent base to work from. While squares are common, hexagons have some advantages, like minimizing those pesky edge effects.

The Old Faithful: “Create Fishnet”

The “Create Fishnet” tool has been around forever in ArcGIS. It’s your go-to for making rectangular grids. Basically, it spits out a feature class full of rectangular cells – a simple but effective starting point. You tell it the area you want to cover, how many rows and columns you need, and boom, you’ve got a grid.

Here’s the lowdown on using Create Fishnet:

“Create Fishnet” is great for squares, but what if you need hexagons or something fancier? That’s where things get interesting.

Hexagons in the Pre-10.3 World: Getting Creative

Alright, so you want hexagons. Since the “Generate Tessellation” tool is out of the question, you’ll need to roll up your sleeves a bit. Here are a few tricks I’ve used over the years:

Things to Keep in Mind

• Coordinate Systems are Key: Make sure your data and grid are in a projected coordinate system that makes sense for your area. Using latitude/longitude can distort your grid, especially if you’re working with specific cell sizes.
• Performance Matters: Creating huge tessellations can bog things down, especially with polygons. If you’re just using the grid for display, consider using polylines instead.
• Shapefile Limitations: If you’re saving to shapefiles, remember the 2GB size limit. I’ve hit this limit more than once! If you’re dealing with a large area, use a file geodatabase instead.
• Consider Upgrading: Seriously, if you can swing it, upgrading to a newer version of ArcGIS Desktop or ArcGIS Pro will make your life so much easier. The “Generate Tessellation” tool is a game-changer.

Final Thoughts

Making tessellations in older versions of ArcGIS Desktop takes a bit more elbow grease, but it’s definitely doable. By understanding the basics and using the tools available – “Create Fishnet,” a bit of math, maybe some Python, or even a third-party tool – you can create the grids you need for your analysis. And hey, sometimes the limitations of older software force you to learn new tricks, which is never a bad thing! Just remember to keep those coordinate systems in check, watch out for performance bottlenecks, and don’t be afraid to get creative.