P3D v4 Aerial imagery alignment issues

[Lukasvez]

Hi,

I am currently working on a small airfield, for which I am compiling the aerial imagery of its area I bought.

Now, here's my problem. I loaded the image into ADE, where only the top left corner's coordinates are required and the image appears exactly where it should be. However, when I compile the image using resample.exe, the image is displaced.

See the pictures attached (and never mind the default runway shown in ADE). You can see that although ADE shows I am on the runway of the aerial image, in P3Dv4 I am actually a bit south of it. This of course also means, that streets, rivers, etc. are also not aligned with the image correctly.

Any ideas?

Thanks!

 

[arno]

Hi,

Is the image you compiled with resample georeferenced already or did you specify the coordinates yourself?

 

[Lukasvez]

Hi Arno,

although I think the imagery might be GeoTIFF, I specified the coordinates by myself. The coordinates of each corner were provided along with the imagery. The coordinates were in UTM format and I had to convert them to decimal degrees.

 

[arno]

Did you reproject the image from UTM to WGS84 as well? Only converting the corner coordinates will not be enough to let resample put it in the right location.

 

[Lukasvez]

No, I didn't. How is this done?
EDIT I used the following link to convert them https://coordvert.com/de/koordinaten-umrechnen/utm/dezimalgrad

 

[arno]

Do you have QGIS or the gdal tools on your computer? You can use those tools to reproject the image.

 

[Lukasvez]

Yes, I do have QGIS. I will search for a guide on Google. Is there by any chance a guide here on FSDeveloper?

Thanks a lot Arno!

 

[arno]

You could try on the OSGeo4W command prompt that comes with QGIS to run this command on your image:

gdal_translate -t_srs "+proj=latlong +datum=WGS84" input.tif output_wgs84.tif

 

[Lukasvez]

Running this command produces the following error:

ERROR 6: Unknown option name '-t_srs'
Usage: gdal_translate [--help-general] [--long-usage]
[-ot {Byte/Int16/UInt16/UInt32/Int32/Float32/Float64/
CInt16/CInt32/CFloat32/CFloat64}] [-strict]
[-of format] [-b band] [-mask band] [-expand {gray|rgb|rgba}]
[-outsize xsize[%]|0 ysize[%]|0] [-tr xres yres]
[-r {nearest,bilinear,cubic,cubicspline,lanczos,average,mode}]
[-unscale] [-scale[_bn] [src_min src_max [dst_min dst_max]]]* [-exponent[_bn] exp_val]*
[-srcwin xoff yoff xsize ysize] [-epo] [-eco]
[-projwin ulx uly lrx lry] [-projwin_srs srs_def]
[-a_srs srs_def] [-a_ullr ulx uly lrx lry] [-a_nodata value]
[-a_scale value] [-a_offset value]
[-gcp pixel line easting northing [elevation]]*
|-colorinterp{_bn} {red|green|blue|alpha|gray|undefined}]
|-colorinterp {red|green|blue|alpha|gray|undefined},...]
[-mo "META-TAG=VALUE"]* [-q] [-sds]
[-co "NAME=VALUE"]* [-stats] [-norat]
[-oo NAME=VALUE]*
src_dataset dst_dataset

BTW, the aerial imagery (which came in 4 tiles) was indeed delivered in GeoTIFF format.

 

[arno]

Sorry, my mistake. Should have been gdalwarp instead of gdal_translate.

 

[Lukasvez]

Hi,

I ran gdalinfo on one of the 4 tiles I have and the result confused me even more. Here's the result:

C:\OSGeo4W64>gdalinfo 633484_5394699.tif
Driver: GTiff/GeoTIFF
Files: 633484_5394699.tif
Size is 11660, 10115
Coordinate System is:
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS 84",6378137,298.257223563,
AUTHORITY["EPSG","7030"]],
AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433],
AUTHORITY["EPSG","4326"]]
Origin = (633484.033000000054017,5396721.983000000007451)
Pixel Size = (0.200000000000000,-0.200000000000000)
Metadata:
AREA_OR_POINT=Area
TIFFTAG_COPYRIGHT=Landesamt fⁿr Digitalisierung, Breitband und Vermessung
TIFFTAG_DATETIME=01.07.2018 00:00:00
TIFFTAG_RESOLUTIONUNIT=3 (pixels/cm)
TIFFTAG_SOFTWARE=Geodaten Bestellung von Matthias Schulze
TIFFTAG_XRESOLUTION=250
TIFFTAG_YRESOLUTION=250
Image Structure Metadata:
INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left ( 633484.033, 5396721.983) (Invalid angle,Invalid angle)
Lower Left ( 633484.033, 5394698.983) (Invalid angle,Invalid angle)
Upper Right ( 635816.033, 5396721.983) (Invalid angle,Invalid angle)
Lower Right ( 635816.033, 5394698.983) (Invalid angle,Invalid angle)
Center ( 634650.033, 5395710.483) (Invalid angle,Invalid angle)
Band 1 Block=11660x8 Type=Byte, ColorInterp=Red
Band 2 Block=11660x8 Type=Byte, ColorInterp=Green
Band 3 Block=11660x8 Type=Byte, ColorInterp=Blue

Does the 6th line mean that the image is already in WGS84 format? And just to make sure, are the corner coordinates indeed in the UTM format?

 

[arno]

Hi,

The coordinates indeed suggest it's UTM, but the georeferencing says it's WGS84 already. Looks like the georeferencing is not correct. In that case you probably first need to set the right coordinate system before you can reproject it.

 

[Lukasvez]

Hi Arno,

is this something I could do myself or would I have to contact the imagery provider about this?

 

[arno]

If you know which UTM zone it is, you can do it yourself.

 

[Shaun]

The image has been cropped it seems? The white border should be equal on all sides.. Have you edited the dimensions of the image?

 

[arno]

No, such a white border is common with reproject ion and it should not be the same everywhere.

 

[Shaun]

No, such a white border is common with reproject ion and it should not be the same everywhere.

OK didn't know that, it's just every time I have done it it has been equal.