From c0a282db0ba148edfb83535cdb335847ac5c5960 Mon Sep 17 00:00:00 2001
From: Luc Maisonobe <luc@orekit.org>
Date: Mon, 20 Oct 2014 12:42:27 +0200
Subject: [PATCH] Further clarifications.
---
.../org/orekit/rugged/raster/TileUpdater.java | 26 +++++++++----------
.../orekit/rugged/raster/UpdatableTile.java | 10 +++++++
2 files changed, 23 insertions(+), 13 deletions(-)
diff --git a/core/src/main/java/org/orekit/rugged/raster/TileUpdater.java b/core/src/main/java/org/orekit/rugged/raster/TileUpdater.java
index 86310a44..ea81174e 100644
--- a/core/src/main/java/org/orekit/rugged/raster/TileUpdater.java
+++ b/core/src/main/java/org/orekit/rugged/raster/TileUpdater.java
@@ -53,23 +53,23 @@ public interface TileUpdater {
* </li>
* <li>
* As elevations are interpolated within Digital Elevation Model
- * pixels using four pixels at indices (i, j), (i+1, j), (i, j+1)
- * (i+1, j+1). A point in the northernmost row (resp. easternmost
- * column) miss neighboring points at row j+1 (resp. neighboring
- * points at column i+1) and therefore cannot be interpolated.
- * The method should therefore select the northernmost tile if the
- * specified latitude is in the overlapping row between two tiles,
- * and it should select the easternmost tile if the specified longitude
- * is in the overlapping column between two tiles. Failing to do so will
- * trigger an error at caller level mentioning the missing required
- * neighbors.
+ * pixels using four pixels at indices (kLat, kLon), (kLat+1, kLon),
+ * (kLat, kLon+1), (kLat+1, kLon+1). A point in the northernmost row
+ * (resp. easternmost column) miss neighboring points at row kLat+1
+ * (resp. neighboring points at column kLon+1) and therefore cannot
+ * be interpolated. The method should therefore select the northernmost
+ * tile if the specified latitude is in the overlapping row between two
+ * tiles, and it should select the easternmost tile if the specified
+ * longitude is in the overlapping column between two tiles. Failing
+ * to do so will trigger an error at caller level mentioning the missing
+ * required neighbors.
* </li>
* <li>
* The elevation at grid point as set when calling {@link
- * UpdatableTile#setElevation(int, int, double) tile.setElevation(i, j,
+ * UpdatableTile#setElevation(int, int, double) tile.setElevation(kLat, kLon,
* elevation)} must be the elevation corresponding to the latitude
- * {@code minLatitude + i * latitudeStep} and longitude {@code
- * minLongitude + j * longitudeStep}, where {@code minLatitude},
+ * {@code minLatitude + kLat * latitudeStep} and longitude {@code
+ * minLongitude + kLon * longitudeStep}, where {@code minLatitude},
* {@code latitudeStep}, {@code minLongitude} and {@code longitudeStep}
* correspond to the parameter of the {@link UpdatableTile#setGeometry(double,
* double, double, double, int, int) tile.setGeometry(minLatitude, minLongitude,
diff --git a/core/src/main/java/org/orekit/rugged/raster/UpdatableTile.java b/core/src/main/java/org/orekit/rugged/raster/UpdatableTile.java
index e296930d..51fb1141 100644
--- a/core/src/main/java/org/orekit/rugged/raster/UpdatableTile.java
+++ b/core/src/main/java/org/orekit/rugged/raster/UpdatableTile.java
@@ -38,6 +38,16 @@ public interface UpdatableTile {
throws RuggedException;
/** Set the elevation for one raster element.
+ * <p>
+ * BEWARE! The order of the indices follows geodetic conventions, i.e.
+ * the latitude is given first and longitude afterwards, so the first
+ * index specifies a <em>row</em> index with zero at South and max value
+ * at North, and the second index specifies a <em>column</em> index
+ * with zero at West and max value at East. This is <em>not</em> the
+ * same as some raster conventions (as our row index increases from South
+ * to North) and this is also not the same as Cartesian coordinates as
+ * our ordinate index appears before our abscissa index).
+ * </p>
* @param latitudeIndex index of latitude (row index)
* @param longitudeIndex index of longitude (column index)
* @param elevation elevation (m)
--
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