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Geostationary projection: speed up inverse spherical and ellipsoidal computation #4523

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rouault merged 2 commits into from
Jun 18, 2025
Merged

Geostationary projection: speed up inverse spherical and ellipsoidal computation #4523

rouault merged 2 commits into from
Jun 18, 2025

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@rouault rouault commented Jun 16, 2025 •
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Fixes #4522

  • Spherical case:
    Before:
$ bin/bench_proj_trans --pipeline "+proj=pipeline +inv +step +proj=geos +h=35785831.0 +lon_0=0 +ellps=sphere" 137881.85 4490747.09
137881.85 4490747.09 -> 0.034807228056148 0.850471730911161
Duration: 677 ms
Throughput: 7.39 million coordinates/s

After:

$ bin/bench_proj_trans --pipeline "+proj=pipeline +inv +step +proj=geos +h=35785831.0 +lon_0=0 +ellps=sphere" 137881.85 4490747.09
137881.85 4490747.09 -> 0.034807228056148 0.850471730911161
Duration: 602 ms
Throughput: 8.31 million coordinates/s
  • Ellipsoidal case:

Before:

$ bin/bench_proj_trans --pipeline "+proj=pipeline +inv +step +proj=geos +h=35785831.0 +lon_0=0 +ellps=WGS84" 137881.85 4490747.09
137881.85 4490747.09 -> 0.0349065842446029 0.855211334383648
Duration: 978 ms
Throughput: 5.11 million coordinates/s

After:

$ bin/bench_proj_trans --pipeline "+proj=pipeline +inv +step +proj=geos +h=35785831.0 +lon_0=0 +ellps=WGS84" 137881.85 4490747.09
137881.85 4490747.09 -> 0.0349065842446029 0.855211334383648
Duration: 668 ms
Throughput: 7.49 million coordinates/s

@rouault
Geostationary projection: speed up inverse ellipsoidal computation
70a066c 
Fixes OSGeo#4522

Before:
```
$ bin/bench_proj_trans --pipeline "+proj=pipeline +inv +step +proj=geos +h=35785831.0 +lon_0=0 +ellps=WGS84" 137881.85 4490747.09
137881.85 4490747.09 -> 0.0349065842446029 0.855211334383648
Duration: 978 ms
Throughput: 5.11 million coordinates/s
```

After:
```
$ bin/bench_proj_trans --pipeline "+proj=pipeline +inv +step +proj=geos +h=35785831.0 +lon_0=0 +ellps=WGS84" 137881.85 4490747.09
137881.85 4490747.09 -> 0.0349065842446029 0.855211334383648
Duration: 668 ms
Throughput: 7.49 million coordinates/s
```
@rouault rouault added this to the 9.7.0 milestone Jun 16, 2025
@rouault rouault mentioned this pull request Jun 16, 2025
Closed
@rouault
Geostationary projection: speed up inverse spherical computation
b005638 
Before:
```
$ bin/bench_proj_trans --pipeline "+proj=pipeline +inv +step +proj=geos +h=35785831.0 +lon_0=0 +ellps=sphere" 137881.85 4490747.09
137881.85 4490747.09 -> 0.034807228056148 0.850471730911161
Duration: 677 ms
Throughput: 7.39 million coordinates/s
```

After:
```
$ bin/bench_proj_trans --pipeline "+proj=pipeline +inv +step +proj=geos +h=35785831.0 +lon_0=0 +ellps=sphere" 137881.85 4490747.09
137881.85 4490747.09 -> 0.034807228056148 0.850471730911161
Duration: 602 ms
Throughput: 8.31 million coordinates/s
```
@rouault rouault changed the title Geostationary projection: speed up inverse ellipsoidal computation Geostationary projection: speed up inverse spherical and ellipsoidal computation Jun 16, 2025
@rouault rouault merged commit 6456f9e into OSGeo:master Jun 18, 2025
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Unecessary calculation in ellipsoidal inverse geos transform

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