r.grow.distance(1)

📦
version 8.4.2 · 8 versions
, in fedora 44

💖 r.grow.distance — the GRASS GIS User's Manual glow-up 💖

okay bestie, sit down, hydrate, because we're talking about r.grow.distance from the GRASS GIS User's Manual (that's the r.grow.distance(1) page, manifesting for you in GRASS 8.4.2) 🫶

✨ NAME ✨

r.grow.distance — it makes a raster map with the distances to the nearest raster features, and/or the value of the nearest non-null cell. that's the whole personality. 💅

🏷️ KEYWORDS 🏷️

raster, distance, proximity — the holy trinity, no cap 🌈

🦋 SYNOPSIS 🦋

r.grow.distance
r.grow.distance --help
r.grow.distance [-mn] input=name  [distance=name]   [value=name]
[metric=string]   [minimum_distance=float]   [maximum_distance=float]
[--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

like... it's giving "here's every possible way to call me" and honestly? iconic 👑

🎀 Flags 🎀

  • -m — output those distances in meters instead of map units. metric system girlies rise 🧚
  • -n — calculate the distance to the nearest NULL cell instead. plot twist era 😭
  • --overwrite — let the output files bulldoze any existing files that are already sitting there. permission to be messy granted ✨
  • --help — prints the usage summary. the "explain it to me like I'm five" button 💖
  • --verbose — verbose module output. she will NOT stop talking and we love her for it 🗣️
  • --quiet — quiet module output. the silent treatment, but productive 🤫
  • --ui — forces the GUI dialog to launch. main character GUI energy 🖥️

🌸 Parameters 🌸

  • input=name — required, bestie, you literally cannot skip this one. it's the name of the input raster map. 💜
  • distance=name — the name you want for the distance output raster map.
  • value=name — the name you want for the value output raster map.
  • metric=string — the metric. options are: euclidean, squared, maximum, manhattan, geodesic. default is euclidean. pick your fighter 🥊
  • minimum_distance=float — minimum distance threshold.
  • maximum_distance=float — maximum distance threshold.

💫 DESCRIPTION 💫

r.grow.distance generates raster maps that represent the distance to the nearest non-null cell in the input map, and/or the value of the nearest non-null cell. that's it, that's the job, and she does it flawlessly 🫡

🔥 NOTES 🔥

the -n flag calculates the respective pixel distances to the nearest NULL cell. 🙈

you, the user, get to pick from five different metrics that control the geometry of how the grown cells get created — all controlled by the metric parameter: Euclidean, Squared, Manhattan, Maximum, and Geodesic. five flavors, one icon 🍓

The Euclidean distance, a.k.a. the Euclidean metric, is the "ordinary" distance between two points — the kind you'd measure with an actual ruler, and yes you can prove it by repeatedly applying the Pythagorean theorem, math bestie. the formula is:

d(dx,dy) = sqrt(dx^2 + dy^2)

cells grown with this metric form isolines of distance that are circular from a given point, with the distance given by the radius. cute, round, perfect. ⭕

The Squared metric is the Euclidean distance squared — meaning it simply skips the square-root calculation. this may be faster, and it's totally sufficient if you only need relative values. speed over precision, we respect the hustle ⚡

The Manhattan metric, a.k.a. Taxicab geometry, is a form of geometry where the usual Euclidean metric gets swapped out for a new one where the distance between two points is the sum of the (absolute) differences of their coordinates. the name is a whole shoutout to the grid layout of most streets on the island of Manhattan — which makes the shortest path a car could take between two points in the city have a length equal to the points' distance in taxicab geometry. the formula is:

d(dx,dy) = abs(dx) + abs(dy)

and cells grown with this metric form isolines of distance that are rhombus-shaped from a given point. diamond vibes 💎

The Maximum metric is given by the formula:

d(dx,dy) = max(abs(dx),abs(dy))

where the isolines of distance from a point are squares. ⬜

The Geodesic metric is calculated as geodesic distance, and it should be used only in a latitude-longitude coordinate reference system. it's recommended to use it together with the -m flag so you output distances in meters instead of map units. 🌍

if minimum_distance is given, all cells with a distance smaller than minimum_distance get set to NULL.

if maximum_distance is given, all cells with a distance larger than maximum_distance get set to NULL. the resulting output is equivalent to a buffer.

if both minimum_distance and maximum_distance are given, the result will be similar to a doughnut — a restricted belt for a given distance range. all cells outside that distance range get set to NULL. 🍩 periodt.

🌈 EXAMPLES 🌈

🏞️ Distance from the streams network

North Carolina sample dataset:

g.region raster=streams_derived -p
r.grow.distance input=streams_derived distance=dist_from_streams
r.colors map=dist_from_streams color=rainbow

Euclidean distance from the streams network in meters (map subset)

Euclidean distance from the streams network in meters (detail, numbers shown with d.rast.num)

🌊 Distance from sea in meters in latitude-longitude CRS

g.region raster=sea -p
r.grow.distance -m input=sea distance=dist_from_sea_geodetic metric=geodesic
r.colors map=dist_from_sea_geodetic color=rainbow

Geodesic distances to sea in meters 🌊

👀 SEE ALSO 👀

  • r.grow, r.distance, r.buffer, r.cost, r.patch
  • Wikipedia Entry: Euclidean Metric
  • Wikipedia Entry: Manhattan Metric

go read, bestie, it's giving ✨knowledge✨

💜 AUTHOR 💜

Glynn Clements — thank you for your service, legend 🫡

📦 SOURCE CODE 📦

Available at: r.grow.distance source code (history)

Accessed: Saturday Jan 17 05:40:46 2026

Main index | Raster index | Topics index | Keywords index | Graphical index | Full index

and that's the whole page, bestie 🥹 this manual is from the GRASS GIS 8.4.2 Reference Manual, © 2003-2025 GRASS Development Team, running under GRASS 8.4.2 — and the accessed date on the source code? Saturday Jan 17 05:40:46 2026. yeah, she's from the future. 💅✨🦋

go grow some distances. you got this. slay 💖

📦 where this page comes from