Extract by Mask and Clip Raster: Different Cuts of the Same Data

This week’s newsletter is brought to you by a conversation I had with Katie Clark , thanks for the inspiration, Katie! We were discussing how to analyze deal with big raster datasets, and I suggested using the Extract by Mask tool to clip the raster data to the area of interest (AOI) and analyze it from there. But it got me thinking about what the key differences are between Extract by Mask and Clip Raster.

Let’s dive into how these tools are similar, how they differ, and the benefits and considerations of using each.

So, what's the same?

Both tools help you focus on a specific area within a raster dataset. In my opinion, they are both essential for refining your datasets, ensuring you’re working with only what you need, and saving processing time and improving map rendering performance.

So, what's different?

• Extract by Mask uses a mask layer (like a polygon) to define the AOI, allowing for more complex shapes and boundaries.
• Clip Raster, on the other hand, uses a rectangular extent aka bounding box to cut the raster, which is straightforward but less flexible for complex shapes.

What are the benefits and considerations of using the Extract by Mask?

• Perfect for irregularly shaped areas: This tool excels when your AOI has complex boundaries that aren't easily captured by a simple rectangle or extent.
• Requires a separate mask layer: You will need a polygon layer to define the mask, so it adds an extra step to your workflow.
• Can be faster: In my experience, it often runs faster than Clip Raster, although there are cases where it might be slower (as shown in my screenshots).
• Requires Spatial Analyst!!

What are the benefits and considerations of using the Clip Raster?

• Efficient for simple extents: Ideal when working with large datasets, especially if your AOI has a simple shape like a rectangle.
• Bounding box for complex shapes: If your boundary is complex, the tool creates a bounding box using the min/max XY coordinates, which may include extra areas outside your AOI.
• No Spatial Analyst needed: Unlike Extract by Mask, Clip Raster does not require additional licenses, making it more accessible for some users.

When I checked back with Katie Clark about how it went with the extract by mask, she was excited to share that after trying Clip Raster (which had been clocked at 56 minutes and counting), she cancelled that process, switched to Extract by Mask, and it finished in just 6 minutes! Now, those are the kinds of results we all hope for!

Next week, we are going to do a shallow dive into model builder!

GIS You Later!

Pro Tip: Need to tweak a feature’s shape? Use Replace Shape; attributes stay the same, saving you time.