From f341e1b2beccae54a94ce8aea3afc227b60d8b31 Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Sat, 14 May 2022 15:31:06 -0700
Subject: [PATCH] [wpimath] Document standard coordinate systems better (NFC)
 (#4228)

---
 .../first/math/geometry/CoordinateSystem.java  | 18 ++++++++++++------
 .../include/frc/geometry/CoordinateSystem.h    | 10 ++++++++--
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/wpimath/src/main/java/edu/wpi/first/math/geometry/CoordinateSystem.java b/wpimath/src/main/java/edu/wpi/first/math/geometry/CoordinateSystem.java
index 93b57312b0..dae9eb8d84 100644
--- a/wpimath/src/main/java/edu/wpi/first/math/geometry/CoordinateSystem.java
+++ b/wpimath/src/main/java/edu/wpi/first/math/geometry/CoordinateSystem.java
@@ -78,9 +78,11 @@ public class CoordinateSystem {
   }
 
   /**
-   * Returns an instance of the NWU coordinate system.
+   * Returns an instance of the North-West-Up (NWU) coordinate system.
    *
-   * @return An instance of the NWU coordinate system.
+   * <p>The +X axis is north, the +Y axis is west, and the +Z axis is up.
+   *
+   * @return An instance of the North-West-Up (NWU) coordinate system.
    */
   @SuppressWarnings("MethodName")
   public static CoordinateSystem NWU() {
@@ -88,9 +90,11 @@ public class CoordinateSystem {
   }
 
   /**
-   * Returns an instance of the EDN coordinate system.
+   * Returns an instance of the East-Down-North (EDN) coordinate system.
    *
-   * @return An instance of the EDN coordinate system.
+   * <p>The +X axis is east, the +Y axis is down, and the +Z axis is north.
+   *
+   * @return An instance of the East-Down-North (EDN) coordinate system.
    */
   @SuppressWarnings("MethodName")
   public static CoordinateSystem EDN() {
@@ -98,9 +102,11 @@ public class CoordinateSystem {
   }
 
   /**
-   * Returns an instance of the NED coordinate system.
+   * Returns an instance of the North-East-Down (NED) coordinate system.
    *
-   * @return An instance of the NED coordinate system.
+   * <p>The +X axis is north, the +Y axis is east, and the +Z axis is down.
+   *
+   * @return An instance of the North-East-Down (NED) coordinate system.
    */
   @SuppressWarnings("MethodName")
   public static CoordinateSystem NED() {
diff --git a/wpimath/src/main/native/include/frc/geometry/CoordinateSystem.h b/wpimath/src/main/native/include/frc/geometry/CoordinateSystem.h
index 9eab85e3b7..8dd6a81f2f 100644
--- a/wpimath/src/main/native/include/frc/geometry/CoordinateSystem.h
+++ b/wpimath/src/main/native/include/frc/geometry/CoordinateSystem.h
@@ -38,17 +38,23 @@ class WPILIB_DLLEXPORT CoordinateSystem {
   CoordinateSystem& operator=(CoordinateSystem&&) = default;
 
   /**
-   * Returns an instance of the NWU coordinate system.
+   * Returns an instance of the North-West-Up (NWU) coordinate system.
+   *
+   * The +X axis is north, the +Y axis is west, and the +Z axis is up.
    */
   static CoordinateSystem NWU();
 
   /**
-   * Returns an instance of the EDN coordinate system.
+   * Returns an instance of the East-Down-North (EDN) coordinate system.
+   *
+   * The +X axis is east, the +Y axis is down, and the +Z axis is north.
    */
   static CoordinateSystem EDN();
 
   /**
    * Returns an instance of the NED coordinate system.
+   *
+   * The +X axis is north, the +Y axis is east, and the +Z axis is down.
    */
   static CoordinateSystem NED();