10. Clip¶

Goal: Crop a layer to a study area boundary using Clip — keeping only the input's attributes.

What clip does¶

Input layer  (everything)        Clip layer (boundary)
[~~~~~~~~~~~~~~~]                ┌──────────┐
[ ~  ~  ~  ~  ~]   +             │  study   │
[~  ~  ~  ~  ~~]                 │  area    │
                                 └──────────┘

         ↓ Clip ↓

Output: only the input geometry inside the boundary,
        with the input layer's attributes only.

Tool location¶

Geoprocessing → Clip (Analysis Tools).

Parameters¶

Parameter	Notes
Input Features	The layer to be cropped
Clip Features	The boundary polygon
Output Feature Class	Where to save
XY Tolerance	Snap distance for messy boundaries

Clip vs Intersect¶

This is the most common "which tool?" confusion.

	Clip	Intersect
Output geometry	Only inside boundary	Only the overlap
Output attributes	Input layer only	All input layers
Use when	"Crop to study area"	"Tag features with what they overlap"

→ Detailed: Buffer vs Clip vs Intersect tutorial.

Clip raster¶

For rasters, use Extract by Mask (Spatial Analyst) or Clip Raster (Data Management).

Common patterns¶

"Streets, but only inside Fulton County"
"Population grid clipped to a watershed"
"Crop a Sentinel-2 scene to a city boundary"
"Tax parcels limited to a planning district"

Pitfalls¶

Coordinate system

Both layers should be in the same projected CRS for accurate boundaries. If one is geographic and the other projected, ArcGIS Pro will reproject behind the scenes — but small errors creep in along the boundary.

Clip first, analyze later

For huge layers (statewide street network), clip to your study area first. The rest of the workflow runs faster.

Practice¶

Clip + Calculate

Add a US national parks polygon and a tree-cover raster (or NDVI).
Clip the raster to one park's polygon (Extract by Mask).
Run Zonal Statistics → mean NDVI per park.

→ Next: Intersect.