Skip to content

Document automatic geodesic scalebar measurement (#7397) #1114

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
szekerest wants to merge 1 commit into
base: main
Choose a base branch
from
+16 −6
Open

Document automatic geodesic scalebar measurement (#7397) #1114

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
11 changes: 8 additions & 3 deletions en/mapfile/scalebar.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,9 +9,14 @@

.. note::

MapServer supports only cartesian distances (straight-line distance measured
on a flat surface), it does not convert distances into an ellipsoidal
distance (measured on a spherical shape).
Starting with MapServer 9.0, when the map has a declared CRS, scalebar
distances are measured geodesically on its ellipsoid using a horizontal
sample centered on the map. The result represents the local horizontal
scale at the map center and may differ from scalebars rendered by earlier
releases, especially in distorted projections. Maps without a CRS retain
Cartesian measurement. If a declared CRS cannot be used for geodesic
measurement, scalebar rendering fails instead of falling back to Cartesian
measurement.

Scalebars currently do not make use of TrueType fonts. The size of the
scalebar image is NOT known prior to rendering, so be careful not to
Expand Down
11 changes: 8 additions & 3 deletions en/utilities/scalebar.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,9 +9,14 @@

.. note::

MapServer supports only cartesian distances (straight-line distance measured
on a flat surface), it does not convert distances into an ellipsoidal
distance (measured on a spherical shape).
Starting with MapServer 9.0, when the map has a declared CRS, scalebar
distances are measured geodesically on its ellipsoid using a horizontal
sample centered on the map. The result represents the local horizontal
scale at the map center and may differ from scalebars rendered by earlier
releases, especially in distorted projections. Maps without a CRS retain
Cartesian measurement. If a declared CRS cannot be used for geodesic
measurement, scalebar rendering fails instead of falling back to Cartesian
measurement.

Purpose
-------
Expand Down
Loading