R Observatory: Metrics for tissot version 0.3.0

Balamuta, James Joseph

doi:10.5281/zenodo.21843040

tissot

0.3.0Package record

Tissot Indicatrix for Map Projection Distortion

0packages depend

1.7Kdownloads / year

–test coverage

13/13flavors OK

Overview

About

Maintained by Michael SumnerCRAN page ↗GitHub ↗Website ↗Issues ↗

Compute and visualize the 'Tissot Indicatrix' for map projections. The indicatrix characterizes projection distortion by computing scale factors, angular deformation, areal distortion, and convergence at arbitrary points. Based on the calculations shared by Bill Huber on https://gis.stackexchange.com/a/5075/482. Uses 'PROJ' for coordinate transformation and distortion factor computation. Developed using the method published in Snyder, JP (1987) doi:10.3133/pp1395.

Changes in 0.3.0

New features

tissot() gains a method argument (default "proj"). The new "proj" method delegates to PROJ::proj_factors(), calling the PROJ C library directly for exact distortion factors rather than approximating them via finite differences. This is more accurate, especially for tabular or piecewise projections (e.g. Robinson). The original finite-difference computation (Snyder 1987), inspired by Bill Huber's formulation at <https://gis.stackexchange.com/a/5075/482>, is preserved as method = "finitediff". The PROJ package is now the sole coordinate transformation dependency; gdalraster has been removed.
tissot_raster() computes distortion surfaces on a regular projected grid, returning a tissot_raster object with image() and plot() methods. Extent is auto-detected from the global lon/lat bounding box (clamped by radius) or supplied explicitly. Supports any metric from [tissot()] output.

Show all changes in 0.3.0Hide the rest of the changes in 0.3.0

Dependency change

gdalraster removed from Imports. All coordinate transformation now goes through PROJ::proj_trans() and PROJ::proj_crs_text(). CRS validation (srs_is_geographic) is handled by an internal helper using PROJ::proj_crs_text().

Bug fixes

Fixed default metrics in tissot_raster(): names now use underscores ("scale_area", "scale_h", "scale_k") matching the actual tissot_tbl column names (previously used dots, causing silently all-NA output).

From NEWS.md in the release

Install

R (CRAN)pak (dev)Ubuntu (r2u)Fedora (COPR)openSUSE (OBS)

install.packages("tissot", repos = "https://cloud.r-project.org/")

Installs the current CRAN release. Prebuilt binaries on Windows and macOS.

if (!requireNamespace("pak", quietly = TRUE))
  install.packages("pak", repos = "https://cloud.r-project.org/")
pak::pak("hypertidy/tissot")

Development version from hypertidy/tissot. Installs pak first if it is not already available.

Release

# enable cranapt (r2u) if it is not already set up, then install
grep -rqs r2u.stat.illinois.edu /etc/apt/sources.list /etc/apt/sources.list.d/ \
  || curl -fsSL https://raw.githubusercontent.com/eddelbuettel/r2u/master/inst/scripts/add_cranapt_noble.sh | sudo bash
sudo apt install -y r-cran-tissot

Fast Ubuntu binaries via r2u (no compilation). The cranapt setup runs once and is skipped when it is already enabled. We list this channel from recorded r2u download activity rather than from a live index of the repository, so treat it as last known rather than guaranteed.

bspm (used by r2u) also needs make: sudo apt install make

# enable the iucar/cran COPR if it is not already present, then install
ls /etc/yum.repos.d/*iucar*cran*.repo >/dev/null 2>&1 \
  || sudo dnf copr enable -y iucar/cran
sudo dnf install -y R-CRAN-tissot

RPMs from the iucar/cran COPR, rebuilt from CRAN.

For install.packages() integration in R, also: sudo dnf install R-CoprManager

# add the autoCRAN OBS repo (Tumbleweed) if it is missing, then install
zypper -q lr | grep -qi autoCRAN \
  || sudo zypper addrepo https://download.opensuse.org/repositories/devel:/languages:/R:/autoCRAN/openSUSE_Tumbleweed/devel:languages:R:autoCRAN.repo
sudo zypper install -y R-tissot

RPMs auto-built from CRAN on openSUSE OBS (Tumbleweed). We list this channel from recorded autoCRAN download activity rather than from a live index of the repository, so treat it as last known rather than guaranteed.

Health

CRAN checks

13OK

CRAN check page ↗

Slowest check: 3.6 min · r-oldrel-macos-x86_64

Status changes

OK13 OK2026-08-04
NOTE12 OK, 1 NOTE2026-08-01
OK13 OK2026-06-09
WARNING12 OK, 1 WARNING2026-06-08
OK14 OK2026-03-10

Advisories

none known

How this is measured·How advisories are found

Documentation

In release 0.3.0

READMEYes · 518 wordsVignettesNoNEWSYes · 100% structured · mentions 0.3.0Citation fileNoWebsiteYes · pkgdown

Help pages: 12 (1 internal)includes a package overview page
Examples that run: 100%8 run in a plain check
Exported functions with examples: 100%
Documented parameters: 100%
Return-value docs: 100%
Help pages citing references: 0%

How these are measured

Downloads

1.7K

CRAN downloads in the past year

Rank #20,237 · ~5/day · ~144/mo

Releases R versions

Daily download trend is not available in this view yet.

24430 days

64290 days

1.7K1 year

Compare downloads with other packages →

Also on58 r2u2 autocran

How downloads are counted

Repository

hypertidy/tissot ↗Organization: hypertidy

19Stars

1Forks

1Open issues

0Open PRs

1Releases

90Commits

2Commit identities

90 commits · Last activity 2026-07-12 · 0% stars, 30d

Responsiveness

How these are sampled

PRs merged (all time): 100%
Median days to close, 50 most recently updated closed issues: 1,772
Median days to close, 50 most recently updated closed PRs: 0

Stars over time

2022-07-04 · 172026-09-12 · 19

How these are measured

PracticesBeta

10 development-tooling and community-health practices detected across 6 families in the upstream repository

Checks run against github.com/hypertidy/tissot on 2026-10-11.

Continuous integration (2)

GitHub ActionsR CMD check workflow

The R CMD check workflow runs on Linux, macOS and Windows, and on R-devel

Governance and community (1)

Code of conduct

Docs source (4)

README.Rmdpkgdown

GitHub Pages site last deployed 2026-07-12 · The repository has a site deploy workflow

pkgdown site last built 2026-07-12

Reproducibility and dev environment (1)

data-raw/

Show all practicesHide 2 practices

CRAN release process (1)

cran-comments.md

Lint, format, editor (1)

RStudio project

How this is detected·Detection ruleset v3 (2026-09-26)

Dependencies

Declared dependencies

6 external dependencies (excludes base and recommended)

Installing tissot adds 12 packages (9 with compiled code, 5.2 MB of source tarballs). Heaviest: vctrs 1.0 MB, wk 1.0 MB, rlang 766 KB.

Depends (1)

R >= 3.6.0

Imports (5)

tibble PROJgraphicsgrDevicesstats

LinkingTo (0)

none

Suggests (4)

testthat knitr rmarkdown spelling

Enhances (0)

none

Dependency license breakdown →

Reverse dependencies

0direct

0indirect

Nothing depends on this yet.

How these are counted

Code & Tests

Datasets

People & History

People (2)

Michael Sumner

Bill Huber

Author

original algorithm and calculations

Releases (2)

Pick two releases to compare their code metrics.

0.3.0Latest
record
2026-07-12 · current release · diff ↗ ·
added 1 export
tissot_raster
R
R 4.6.0 released · 2026-04-24
0.2.0
record
2026-02-12
R
R 4.5.0 released · 2025-04-11

Package metadata

First published: 2026-02-12
Total releases: 2 / 1 yrs
License: MIT + file LICENSE OSI
Minimum R: ≥ 3.6.0
Bundled data: 373 KB / 1 file
Download size: 1.5 MB

Cite

Cite this package

Run in R for the authors' preferred citation:

citation("tissot")

Format

Sumner, M., & Huber, B. (2026). tissot: Tissot Indicatrix for Map Projection Distortion (Version 0.3.0) [Computer software]. https://doi.org/10.32614/CRAN.package.tissot

This package has no citation file, so citation() returns this entry built from DESCRIPTION.

Cite the R Observatory

For a number measured here: a download total, a coverage figure, an archival date.

Format

APA

Balamuta, J. J. (2026). R Observatory: Metrics for tissot version 0.3.0 [Data set]. HJJB, LLC. Data release v2026-10-18. https://doi.org/10.5281/zenodo.21843040

From data release v2026-10-18, which the citation names so these numbers can be found later. More on citing and the projects behind them.

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