Skip to content
GeoJibe

Clip, simplify, or buffer geometry

Need to keep only part of a layer, lighten detailed shapes, or draw a zone around points and lines?

Do that in Transform. Geometry tools sit next to field and row changes. The Canvas stays:

Note

Transform is optional. Clip, Simplify, and Buffer are extra operations inside Transform — not extra Canvas nodes.

Before you start

Inspect the Source so GeoJibe knows the geometry type and coordinate system.

Values you type for clip coordinates, simplify tolerance, and buffer distance use source CRS units. If the layer is EPSG:4326, that means degrees, not metres. GeoJibe will say so on the form.

Clip

Keep only the part of your data inside an area.

Features that cross the edge are cut to that boundary. Attributes are kept. Features completely outside are removed.

  1. Add Transform and click Add transformation.
  2. Under Geometry, choose Clip.
  3. Clip using a Bounding box, then enter Min X, Min Y, Max X, and Max Y in the source CRS.

You can also paste a Polygon or MultiPolygon as WKT or GeoJSON.

Clip does not take another Source as input.

Simplify

Reduce geometry detail to make data smaller or lighter.

  1. Choose Simplify.
  2. Enter a Tolerance in source CRS units.
  3. Leave Preserve topology on unless you have a reason to turn it off.

A larger tolerance removes more vertices. The geometry family stays the same (a line stays a line).

Buffer

Create an area around points, lines, or polygons.

Input Result
Point Polygon
Line Polygon
Polygon Polygon
  1. Choose Buffer.
  2. Enter a Distance in source CRS units.
  3. Open Advanced options only if you need extra roundness (quadrant segments).

A negative distance is allowed for polygons (an inset). It is not used for points or lines.

Expressions

Calculate values or select features using more advanced conditions.

Compute column and Filter rows each have a Simple mode and an Expression mode.

Simple Compute still uses + - * / with field names, for example shape_area / 10000 into hectares.

Expression mode can use comparisons and AND / OR, for example:

population / area_km2

population > 10000 AND status = 'active'

This is not a database console. You cannot run SELECT statements. See Expression syntax for the full list.

After you add an operation

The Transform list shows a short summary, for example:

Clip
Bounding box: -88.1, 41.6 → -87.5, 42.1

Buffer
0.01 degrees

Use edit, delete, and the arrows to reorder. Geometry operations run in the same list order as field operations.

Output Fields still lists attributes only. Geometry is always kept.

Preview shows attribute changes. Clip, Simplify, and Buffer apply when you Run.

See also