From c3eae0347cb511c8c36e4e13d9c91dfa97f643c7 Mon Sep 17 00:00:00 2001
From: kalbl <kallebladin@gmail.com>
Date: Tue, 25 Oct 2016 23:32:08 +0200
Subject: [PATCH] Add default geo transform for global maps if it is not
 specified.

---
 modules/globebrowsing/tile/tiledataset.cpp | 32 +++++++++++++++-------
 modules/globebrowsing/tile/tiledataset.h   | 11 +++++++-
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/modules/globebrowsing/tile/tiledataset.cpp b/modules/globebrowsing/tile/tiledataset.cpp
index 2bd8b5660e..d69042857f 100644
--- a/modules/globebrowsing/tile/tiledataset.cpp
+++ b/modules/globebrowsing/tile/tiledataset.cpp
@@ -438,8 +438,24 @@ namespace globebrowsing {
     }
 
 
-
-
+    std::array<double, 6> TileDataset::getGeoTransform() const {
+        std::array<double, 6> padfTransform;
+        CPLErr err = _dataset->GetGeoTransform(&padfTransform[0]);
+        if (err == CE_Failure) {
+            GeodeticPatch globalCoverage(Geodetic2(0,0), Geodetic2(M_PI / 2, M_PI));
+            padfTransform[1] = Angle<Scalar>::fromRadians(
+                globalCoverage.size().lon).asDegrees() / _dataset->GetRasterXSize();
+            padfTransform[5] = -Angle<Scalar>::fromRadians(
+                globalCoverage.size().lat).asDegrees() / _dataset->GetRasterYSize();
+            padfTransform[0] = Angle<Scalar>::fromRadians(
+                globalCoverage.getCorner(Quad::NORTH_WEST).lon).asDegrees();
+            padfTransform[3] = Angle<Scalar>::fromRadians(
+                globalCoverage.getCorner(Quad::NORTH_WEST).lat).asDegrees();
+            padfTransform[2] = 0;
+            padfTransform[4] = 0;
+        }
+        return padfTransform;
+    }
 
     //////////////////////////////////////////////////////////////////////////////////
     //                          ReadTileData helper functions                       //
@@ -447,11 +463,8 @@ namespace globebrowsing {
 
     PixelCoordinate TileDataset::geodeticToPixel(const Geodetic2& geo) const {
 
-        double padfTransform[6];
-        CPLErr err = _dataset->GetGeoTransform(padfTransform);
-
-        ghoul_assert(err != CE_Failure, "Failed to get transform");
-
+        std::array<double, 6> padfTransform = getGeoTransform();
+        
         Scalar Y = Angle<Scalar>::fromRadians(geo.lat).asDegrees();
         Scalar X = Angle<Scalar>::fromRadians(geo.lon).asDegrees();
 
@@ -484,10 +497,9 @@ namespace globebrowsing {
     }
 
     Geodetic2 TileDataset::pixelToGeodetic(const PixelCoordinate& p) const {
-        double padfTransform[6];
-        CPLErr err = _dataset->GetGeoTransform(padfTransform);
-        ghoul_assert(err != CE_Failure, "Failed to get transform");
+        std::array<double, 6> padfTransform = getGeoTransform();
         Geodetic2 geodetic;
+        // Should be using radians and not degrees?
         geodetic.lon = padfTransform[0] + p.x * padfTransform[1] + p.y * padfTransform[2];
         geodetic.lat = padfTransform[3] + p.x * padfTransform[4] + p.y * padfTransform[5];
         return geodetic;
diff --git a/modules/globebrowsing/tile/tiledataset.h b/modules/globebrowsing/tile/tiledataset.h
index 61bd368880..7bf49b45ad 100644
--- a/modules/globebrowsing/tile/tiledataset.h
+++ b/modules/globebrowsing/tile/tiledataset.h
@@ -147,6 +147,15 @@ namespace globebrowsing {
         //                          ReadTileData helper functions                       //
         //////////////////////////////////////////////////////////////////////////////////
 
+        /**
+         Returns the geo transform from raster space to projection coordinates as defined
+         by GDAL.
+
+         If the transform is not available, the function returns a transform to map
+         the pixel coordinates to cover the whole geodetic lat long space.
+        */
+        std::array<double, 6> getGeoTransform() const;
+
         PixelCoordinate geodeticToPixel(const Geodetic2& geo) const;
         Geodetic2 pixelToGeodetic(const PixelCoordinate& p) const;
         IODescription getIODescription(const TileIndex& tileIndex) const;
@@ -189,4 +198,4 @@ namespace globebrowsing {
 } // namespace globebrowsing
 } // namespace openspace
 
-#endif  // __TILE_DATASET_H__
\ No newline at end of file
+#endif  // __TILE_DATASET_H__