Gdalwarp Issues...

[Shaun]

I have a set of Geotiffs which aren't warping correctly to WGS_84.

The NW should be at 36.913147222222221, -76.218038888888884, which appears correct in the unwarped geotiff, but goes to below -100 deg latitude when warped.

The script I use works fine for many others.

I can't figure out how to solve this.

gtf. is
Geotiff_Information:
Version: 1
Key_Revision: 1.0
Tagged_Information:
ModelTiepointTag (2,3):
0 0 0
12150000 3500000 0
ModelPixelScaleTag (1,3):
1 1 0
End_Of_Tags.
Keyed_Information:
GTModelTypeGeoKey (Short,1): ModelTypeProjected
GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
GTCitationGeoKey (Ascii,55): "NAD_1983_HARN_StatePlane_Virginia_South_FIPS_4502_Feet"
GeogCitationGeoKey (Ascii,12): "NAD83(HARN)"
GeogAngularUnitsGeoKey (Short,1): Angular_Degree
ProjectedCSTypeGeoKey (Short,1): Unknown-2854
ProjLinearUnitsGeoKey (Short,1): Linear_Foot_US_Survey
End_Of_Keys.
End_Of_Geotiff.

PCS = 2854 (NAD83(HARN) / Virginia South)
Projection = 14532 (SPCS83 Virginia South zone (meters))
Projection Method: CT_LambertConfConic_2SP
ProjFalseOriginLatGeoKey: 36.333333 ( 36d20' 0.00"N)
ProjFalseOriginLongGeoKey: -78.500000 ( 78d30' 0.00"W)
ProjStdParallel1GeoKey: 37.966667 ( 37d58' 0.00"N)
ProjStdParallel2GeoKey: 36.766667 ( 36d46' 0.00"N)
ProjFalseEastingGeoKey: 3500000.000000 m
ProjFalseNorthingGeoKey: 1000000.000000 m
GCS: 4152/NAD83(HARN)
Datum: 6152/NAD83 (High Accuracy Reference Network)
Ellipsoid: 7019/GRS 1980 (6378137.00,6356752.31)
Prime Meridian: 8901/Greenwich (0.000000/ 0d 0' 0.00"E)
Projection Linear Units: 9003/US survey foot (0.304801m)

Corner Coordinates:
Upper Left (12150000.000, 3500000.000)
Lower Left (12150000.000, 3485000.000)
Upper Right (12160000.000, 3500000.000)
Lower Right (12160000.000, 3485000.000)
Center (12155000.000, 3492500.000)


Script I use is:
gdalwarp -of GTiff -co "INTERLEAVE=PIXEL" -t_srs "+proj=latlong +datum=WGS84" -r cubic "1.tif" "2.tif" "3.tif" "4.tif" "5.tif" "6.tif" "Norfolk.tif"

If anyone can help, I'd appreciate that very much!

 

[arno]

Hi,

It's hard to say with this information, do you maybe have a link to one of the files to try? Normally projecting to WGS84 like that should work.

The only thing that goes through my mind is that the units (survey feet) of your source are not handled correctly.

 

[Shaun]

I read on the USGS that some geotiffs are affected by a software problem which affects them this way. Could possibly be the reason.

I have another year's version which seems to be exactly the same dimensions, I've copied the tags from onto this new one, might be off a little though, not checked yet.

Here's the original merged geotiff (not reprojected): https://drive.google.com/file/d/0B_aShesvH9iYNXpFd3VFMjhjeHc/view?usp=sharing

Thanks very much.

 

[Shaun]

Hey don't worry about it. It's negligibly better and it'll take too much time to re-do it all. Thanks anyhow!

 

[arno]

Ok, out of interest I might still check the file later if I have time.

 

[Shaun]

USGS has released new imagery, but it's afflicted by the same problem. Gdalinfo gives exactly the same coordinates as the one I'm using. So I'm going to copy the tags, put it onto the new one then warp it. But it might not exactly line up again.

If you could have a look see and work out a correct gdalwarp command, I would be most appreciative.

https://drive.google.com/file/d/0B_aShesvH9iYVEZIMGxKRWdlYVk/view?usp=sharing

 

[Shaun]

Seems the tag thing works okay. Shame that I've spent like a whole week on that photoscenery.

 

[NoNewMessages]

I don't know nothing 'bout no gdalwarping, nor do I have a desire to learn...

It's been posted before that if you want to reproject a GeoTiff to FSX standards, then this little tool makes it easy; http://freegeographytools.com/2009/tritonrmp-helper-upgraded-to-version-2-0

This is what it used in it's batch file to convert, fwiw;

gdalwarp -t_srs "EPSG:4326" -r near -multi "F:\ScenMod\Terrain tools\TritonRMP Helper\Norfolk.tif" "F:\ScenMod\Terrain tools\TritonRMP Helper\Norfolk_geo.tif"
listgeo -tfw "F:\ScenMod\Terrain tools\TritonRMP Helper\Norfolk_geo.tif"

 

[Shaun]

Thanks, I'm using OSGeo4W and use (as the fist post shows) use the gdalwarp to reproject to WGS84. The problem is that the geotiffs seem to have the wrong coordinates embedded into them in the fist place.

 

[NoNewMessages]

Here's what comes out of the GeoTiff after converting, isn't this where Norfolk is?

0.0000029544
0.0000000000
0.0000000000
-0.0000029544
-76.2192769170
36.9131467848

 

[Shaun]

The coordinates are right in the first place, my mistake. But the this script doesn't work in this scenario:

gdalwarp -of GTiff -co "INTERLEAVE=PIXEL" -t_srs "+proj=latlong +datum=WGS84" -r cubic "1.tif" "2.tif" "3.tif" "4.tif" "5.tif" "6.tif" "Norfolk.tif"

I don't understand this python language, why is your script different? What are you reprojecting it into as you haven't defined WGS84.

 

[arno]

EPSG 4326 is also wgs84. So these batch files are similar.

I'll try to check the files later this evening.