GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages
v.fill.holes(1) GRASS GIS User's Manual v.fill.holes(1)

v.fill.holes - Fill holes in areas by keeping only outer boundaries

vector, geometry, fill, exterior, ring, perimeter

v.fill.holes
v.fill.holes --help
v.fill.holes input=name [layer=string] [cats=range] [where=sql_query] output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]


Allow output files to overwrite existing files

Print usage summary

Verbose module output

Quiet module output

Force launching GUI dialog


Name of input vector map
Or data source for direct OGR access

Layer number or name
Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
Default: 1

Category values
Example: 1,3,7-9,13

WHERE conditions of SQL statement without ’where’ keyword
Example: income < 1000 and population >= 10000

Name for output vector map

v.fill.holes fills empty spaces inside areas, specifically it preserves areas with centroids while areas without centroids, which typically represent holes, are removed. v.fill.holes goes over all areas in a vector map and it preserves only outer boundaries of each area while removing inner boundaries which are considered holes. The holes become part of the area which contained them. No boundaries of these holes are preserved.
Figure: Holes inside areas are removed. (a) Original areas with holes and (b) the same areas but with holes filled. In case areas have empty space in between them, i.e., there are holes in the overall coverage, but not in the areas themselves, v.fill.holes can’t assign this empty space to either of these areas because it does not know which area this empty space should belong to. If the space needs to be filled, this can be resolved by merging the areas around the empty space into one by dissolving their common boundaries. This turns the empty space into a hole inside one single area which turns the situation into a case of one area with a hole.
Figure: Empty space in between two areas does not belong to either area, so it is filled only after the boundaries between areas are dissolved, i.e., areas merged into one. (a) Original areas with space in between, (b) one area with a hole after dissolving the common boundary, and (c) hole filled.

Strictly speaking, in the GRASS topological model, an area is a closed boundary (or a series of connected closed boundaries) which may have a centroid. If it has a centroid, it is rendered as a filled area in displays and this is what is usually considered an area from the user perspective. These are the areas where v.fill.holes preserves the associated outer boundary (or boundaries). Other closed boundaries, i.e., those without a centroid, are not carried over to the output. All other features are removed including points and lines.

If a specific layer is selected, attributes for that layer are preserved for the areas based on the category or categories associated with each area. By default, layer number 1 is selected. In case there are attribute tables associated with other layers or attributes associated with categories of other features than areas with centroids, this attribute data is not carried over to the output just like the corresponding geometries.

The lakes vector map in the North Carolina sample dataset represents islands inside lakes as areas distinguished by attributes. To demonstrate v.fill.holes, we will first extract only the lakes which will create holes where the islands were located. Then, we will fill the holes created in the lakes to get the whole perimeter of the lakes including islands. Remove the islands by extracting everything else (results in holes):

v.extract input=lakes where="FTYPE != ’ROCK/ISLAND’" output=lakes_only

Remove the holes:

v.fill.holes input=lakes_only output=lakes_filled

Figure: The filled lake (blue) and borders of the original lakes with islands removed (light blue). Figure shows a smaller area in the north of the data extent.

  • v.dissolve for removing common boundaries based on attributes,
  • v.clean for removing topological issues,
  • r.fillnulls for filling empty spaces in raster maps using interpolation,
  • r.fill.stats for filling empty spaces in raster maps using statistics.

Vaclav Petras, NCSU Center for Geospatial Analytics, GeoForAll Lab

Available at: v.fill.holes source code (history)

Latest change: Tuesday Apr 23 10:45:15 2024 in commit: f8115df1219e784a7136e7609f4c9bb16d928e2f

Main index | Vector index | Topics index | Keywords index | Graphical index | Full index

© 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual

GRASS 8.4.1

Search for    or go to Top of page |  Section 1 |  Main Index

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with ManDoc.