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I collected four drone flights for DEM and orthomosaic creation. While all flights overlapped, each of the datasets has different vertical elevation ranges (because of the internal inconsistency).

How do I correct three of the flights to be accurate (although relative) extensions of one flight's elevation range?

I've been trying to mosaic the rasters in ArcGIS Pro. However, I'm not sure where to specify specific elevations, or to mosaic/resample based off one of the rasters.

I did not use GCPs but have various reference coordinates from images the drone took before take-off (XYZ in the header files).

Update Nov 1 Two images EXIF info covering the same location, two different flights.

--Image 1---

ExifTool Version Number         : 12.34
Warning                         : [minor] Possibly incorrect maker notes offsets (fix by 1783?)
---- System ----
File Name                       : DJI_0077.JPG
Directory                       : C:/Users/user/Desktop/Active Projects/Field Data 2021/UAV/oct52021
File Size                       : 7.8 MiB
File Modification Date/Time     : 2021:10:05 09:57:22-06:00
File Access Date/Time           : 2021:11:01 16:48:22-06:00
File Creation Date/Time         : 2021:10:05 22:05:23-06:00
File Permissions                : -rw-rw-rw-
---- File ----
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
Exif Byte Order                 : Little-endian (Intel, II)
Image Width                     : 4864
Image Height                    : 3648
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:2 (2 1)
---- IFD0 ----
Image Description               : DCIM\103MEDIA\DJI_0077.JPG
Make                            : DJI
Camera Model Name               : FC6310
Orientation                     : Horizontal (normal)
X Resolution                    : 72
Y Resolution                    : 72
Resolution Unit                 : inches
Software                        : v01.07.1641
Modify Date                     : 2021:10:05 09:57:22
Y Cb Cr Positioning             : Centered
XP Comment                      : Type=N, Mode=P, DE=None
XP Keywords                     : v01.07.1641;1.2.0;v1.0.0
---- ExifIFD ----
Exposure Time                   : 1/320
F Number                        : 5.0
Exposure Program                : Program AE
ISO                             : 100
Exif Version                    : 0230
Date/Time Original              : 2021:10:05 09:57:21
Create Date                     : 2021:10:05 09:57:21
Components Configuration        : -, Cr, Cb, Y
Compressed Bits Per Pixel       : 3.538154017
Shutter Speed Value             : 1/320
Aperture Value                  : 5.0
Exposure Compensation           : 0
Max Aperture Value              : 2.8
Subject Distance                : 0 m
Metering Mode                   : Center-weighted average
Light Source                    : Daylight
Flash                           : No flash function
Focal Length                    : 8.8 mm
Flashpix Version                : 0010
Color Space                     : sRGB
Exif Image Width                : 4864
Exif Image Height               : 3648
Exposure Index                  : undef
File Source                     : Digital Camera
Scene Type                      : Directly photographed
Custom Rendered                 : Normal
Exposure Mode                   : Auto
White Balance                   : Auto
Digital Zoom Ratio              : undef
Focal Length In 35mm Format     : 24 mm
Scene Capture Type              : Standard
Gain Control                    : None
Contrast                        : Normal
Saturation                      : Normal
Sharpness                       : Hard
Subject Distance Range          : Unknown
Serial Number                   : fbf16121c5a52d6315bf9c38316bf7f2
---- DJI ----
Make                            : DJI
DJI 0x0002                      : 1 3 0 0
Speed X                         : -5.40
Speed Y                         : +0.00
Speed Z                         : +0.00
Pitch                           : -4.20
Yaw                             : -176.50
Roll                            : -3.80
Camera Pitch                    : -89.90
Camera Yaw                      : -177.50
Camera Roll                     : +0.00
DJI 0x000c                      : 9.18397000533842e-041 9.18354961579912e-041
DJI 0x000d                      : 2684485632 65540 318767104 2684551168
DJI 0x000e                      : 8
DJI 0x000f                      : 0
DJI 0x0010                      : 38
DJI 0x0011                      : 0
DJI 0x0012                      : 0
DJI 0x0013                      : 65540 239075328 -1610285056 65540 42991616
DJI 0x0014                      : 2719285248 65541 653721600
DJI 0x0017                      : 1
DJI 0x0019                      : 48
DJI 0x001a                      : 0
DJI 0x001b                      : 1
DJI 0x001c                      : 131
DJI 0x001d                      : 133
DJI 0x001e                      : 12.8984336853027
DJI 0x001f                      : 12.8984336853027
DJI 0x0020                      : 0
DJI 0x0021                      : 0
DJI 0x0022                      : 0
DJI 0x0023                      : 0
DJI 0x0026                      : -6.93889390390723e-018 9.18453052472415e-041 2.75506488[...]
DJI 0x0027                      : 65543 65536 2751528960 65539
DJI 0x0024                      : 0 0 0 0 0 0 2 164 3 0 1 0 0 0 0 0 0 0 3 164 3 0 1 0 0 0[...]
---- InteropIFD ----
Interoperability Index          : R98 - DCF basic file (sRGB)
Interoperability Version        : 0100
---- GPS ----
GPS Version ID                  : 2.3.0.0
GPS Latitude Ref                : North
GPS Latitude                    : 49 deg 19' 48.02"
GPS Longitude Ref               : West
GPS Longitude                   : 113 deg 10' 7.39"
GPS Altitude Ref                : Above Sea Level
GPS Altitude                    : 1225.493 m
---- IFD1 ----
Compression                     : JPEG (old-style)
X Resolution                    : 72
Y Resolution                    : 72
Resolution Unit                 : inches
Thumbnail Offset                : 10240
Thumbnail Length                : 10117
Thumbnail Image                 : (Binary data 10117 bytes, use -b option to extract)
---- XMP-rdf ----
About                           : DJI Meta Data
---- XMP-xmp ----
Modify Date                     : 2021:10:05
Create Date                     : 2021:10:05
---- XMP-tiff ----
Make                            : DJI
Camera Model Name               : FC6310
---- XMP-dc ----
Format                          : image/jpg
---- XMP-drone-dji ----
Absolute Altitude               : +1225.49
Relative Altitude               : +79.90
Gimbal Roll Degree              : +0.00
Gimbal Yaw Degree               : -177.50
Gimbal Pitch Degree             : -89.90
Flight Roll Degree              : -3.80
Flight Yaw Degree               : -176.50
Flight Pitch Degree             : -4.20
Cam Reverse                     : 0
Gimbal Reverse                  : 0
Self Data                       : 615c726b4c4ecd4445878ca34.59.0
Calibrated Focal Length         : 3666.666504
Calibrated Optical Center X     : 2432.000000
Calibrated Optical Center Y     : 1824.000000
Rtk Flag                        : 0
---- XMP-crs ----
Version                         : 7.0
Has Settings                    : False
Has Crop                        : False
Already Applied                 : False
---- MPF0 ----
MPF Version                     : 0010
Number Of Images                : 2
Image UID List                  : (Binary data 66 bytes, use -b option to extract)
Total Frames                    : 1
---- MPImage1 ----
MP Image Flags                  : Representative image, Dependent parent image
MP Image Format                 : JPEG
MP Image Type                   : Baseline MP Primary Image
MP Image Length                 : 7876262
MP Image Start                  : 0
Dependent Image 1 Entry Number  : 0
Dependent Image 2 Entry Number  : 2
---- MPImage2 ----
MP Image Flags                  : Dependent child image
MP Image Format                 : JPEG
MP Image Type                   : Large Thumbnail (VGA equivalent)
MP Image Length                 : 257321
MP Image Start                  : 7876262
Dependent Image 1 Entry Number  : 0
Dependent Image 2 Entry Number  : 0
Preview Image                   : (Binary data 257321 bytes, use -b option to extract)
---- Composite ----
Aperture                        : 5.0
Image Size                      : 4864x3648
Megapixels                      : 17.7
Scale Factor To 35 mm Equivalent: 2.7
Shutter Speed                   : 1/320
GPS Altitude                    : 1225.4 m Above Sea Level
GPS Latitude                    : 49 deg 19' 48.02" N
GPS Longitude                   : 113 deg 10' 7.39" W
Circle Of Confusion             : 0.011 mm
Field Of View                   : 73.7 deg
Focal Length                    : 8.8 mm (35 mm equivalent: 24.0 mm)
GPS Position                    : 49 deg 19' 48.02" N, 113 deg 10' 7.39" W
Hyperfocal Distance             : 1.41 m
Light Value                     : 13.0

---Image 2----

---- ExifTool ----
ExifTool Version Number         : 12.34
Warning                         : [minor] Possibly incorrect maker notes offsets (fix by 1783?)
---- System ----
File Name                       : DJI_0820.JPG
Directory                       : C:/Users/user/Desktop/Active Projects/Field Data 2021/UAV/Oct42021
File Size                       : 7.2 MiB
File Modification Date/Time     : 2021:10:04 10:05:58-06:00
File Access Date/Time           : 2021:11:01 16:45:59-06:00
File Creation Date/Time         : 2021:10:04 18:44:57-06:00
File Permissions                : -rw-rw-rw-
---- File ----
File Type                       : JPEG
File Type Extension             : jpg
MIME Type                       : image/jpeg
Exif Byte Order                 : Little-endian (Intel, II)
Image Width                     : 4864
Image Height                    : 3648
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:2 (2 1)
---- IFD0 ----
Image Description               : DCIM\102MEDIA\DJI_0820.JPG
Make                            : DJI
Camera Model Name               : FC6310
Orientation                     : Horizontal (normal)
X Resolution                    : 72
Y Resolution                    : 72
Resolution Unit                 : inches
Software                        : v01.07.1641
Modify Date                     : 2021:10:04 10:05:57
Y Cb Cr Positioning             : Centered
XP Comment                      : Type=N, Mode=P, DE=None
XP Keywords                     : v01.07.1641;1.2.0;v1.0.0
---- ExifIFD ----
Exposure Time                   : 1/320
F Number                        : 5.0
Exposure Program                : Program AE
ISO                             : 100
Exif Version                    : 0230
Date/Time Original              : 2021:10:04 10:05:57
Create Date                     : 2021:10:04 10:05:57
Components Configuration        : -, Cr, Cb, Y
Compressed Bits Per Pixel       : 3.257353074
Shutter Speed Value             : 1/320
Aperture Value                  : 5.0
Exposure Compensation           : 0
Max Aperture Value              : 2.8
Subject Distance                : 0 m
Metering Mode                   : Center-weighted average
Light Source                    : Daylight
Flash                           : No flash function
Focal Length                    : 8.8 mm
Flashpix Version                : 0010
Color Space                     : sRGB
Exif Image Width                : 4864
Exif Image Height               : 3648
Exposure Index                  : undef
File Source                     : Digital Camera
Scene Type                      : Directly photographed
Custom Rendered                 : Normal
Exposure Mode                   : Auto
White Balance                   : Auto
Digital Zoom Ratio              : undef
Focal Length In 35mm Format     : 24 mm
Scene Capture Type              : Standard
Gain Control                    : None
Contrast                        : Normal
Saturation                      : Normal
Sharpness                       : Hard
Subject Distance Range          : Unknown
Serial Number                   : fbf16121c5a52d6315bf9c38316bf7f2
---- DJI ----
Make                            : DJI
DJI 0x0002                      : 1 3 0 0
Speed X                         : -0.10
Speed Y                         : -1.00
Speed Z                         : +1.70
Pitch                           : -2.10
Yaw                             : +19.00
Roll                            : -6.90
Camera Pitch                    : -90.00
Camera Yaw                      : +15.20
Camera Roll                     : +0.00
DJI 0x000c                      : 9.18397000533842e-041 9.18354961579912e-041
DJI 0x000d                      : 2684485632 65540 318767104 2684551168
DJI 0x000e                      : 8
DJI 0x000f                      : 0
DJI 0x0010                      : 38
DJI 0x0011                      : 0
DJI 0x0012                      : 0
DJI 0x0013                      : 65540 239075328 -1610285056 65540 42991616
DJI 0x0014                      : 2719285248 65541 653721600
DJI 0x0017                      : 1
DJI 0x0019                      : 48
DJI 0x001a                      : 0
DJI 0x001b                      : 1
DJI 0x001c                      : 131
DJI 0x001d                      : 131
DJI 0x001e                      : 12.8203067779541
DJI 0x001f                      : 12.8203067779541
DJI 0x0020                      : 0
DJI 0x0021                      : 0
DJI 0x0022                      : 0
DJI 0x0023                      : 0
DJI 0x0026                      : -6.93889390390723e-018 9.18453052472415e-041 2.75506488[...]
DJI 0x0027                      : 65543 65536 2751528960 65539
DJI 0x0024                      : 0 0 0 0 0 0 2 164 3 0 1 0 0 0 0 0 0 0 3 164 3 0 1 0 0 0[...]
---- InteropIFD ----
Interoperability Index          : R98 - DCF basic file (sRGB)
Interoperability Version        : 0100
---- GPS ----
GPS Version ID                  : 2.3.0.0
GPS Latitude Ref                : North
GPS Latitude                    : 49 deg 19' 47.91"
GPS Longitude Ref               : West
GPS Longitude                   : 113 deg 10' 4.89"
GPS Altitude Ref                : Above Sea Level
GPS Altitude                    : 1178.61 m
---- IFD1 ----
Compression                     : JPEG (old-style)
X Resolution                    : 72
Y Resolution                    : 72
Resolution Unit                 : inches
Thumbnail Offset                : 10240
Thumbnail Length                : 11589
Thumbnail Image                 : (Binary data 11589 bytes, use -b option to extract)
---- XMP-rdf ----
About                           : DJI Meta Data
---- XMP-xmp ----
Modify Date                     : 2021:10:04
Create Date                     : 2021:10:04
---- XMP-tiff ----
Make                            : DJI
Camera Model Name               : FC6310
---- XMP-dc ----
Format                          : image/jpg
---- XMP-drone-dji ----
Absolute Altitude               : +1178.61
Relative Altitude               : +80.20
Gimbal Roll Degree              : +0.00
Gimbal Yaw Degree               : +15.20
Gimbal Pitch Degree             : -90.00
Flight Roll Degree              : -6.90
Flight Yaw Degree               : +19.00
Flight Pitch Degree             : -2.10
Cam Reverse                     : 0
Gimbal Reverse                  : 0
Self Data                       : 615b262a944a8f595176b1ed4.59.0
Calibrated Focal Length         : 3666.666504
Calibrated Optical Center X     : 2432.000000
Calibrated Optical Center Y     : 1824.000000
Rtk Flag                        : 0
---- XMP-crs ----
Version                         : 7.0
Has Settings                    : False
Has Crop                        : False
Already Applied                 : False
---- MPF0 ----
MPF Version                     : 0010
Number Of Images                : 2
Image UID List                  : (Binary data 66 bytes, use -b option to extract)
Total Frames                    : 1
---- MPImage1 ----
MP Image Flags                  : Representative image, Dependent parent image
MP Image Format                 : JPEG
MP Image Type                   : Baseline MP Primary Image
MP Image Length                 : 7254922
MP Image Start                  : 0
Dependent Image 1 Entry Number  : 0
Dependent Image 2 Entry Number  : 2
---- MPImage2 ----
MP Image Flags                  : Dependent child image
MP Image Format                 : JPEG
MP Image Type                   : Large Thumbnail (VGA equivalent)
MP Image Length                 : 255629
MP Image Start                  : 7254922
Dependent Image 1 Entry Number  : 0
Dependent Image 2 Entry Number  : 0
Preview Image                   : (Binary data 255629 bytes, use -b option to extract)
---- Composite ----
Aperture                        : 5.0
Image Size                      : 4864x3648
Megapixels                      : 17.7
Scale Factor To 35 mm Equivalent: 2.7
Shutter Speed                   : 1/320
GPS Altitude                    : 1178.6 m Above Sea Level
GPS Latitude                    : 49 deg 19' 47.91" N
GPS Longitude                   : 113 deg 10' 4.89" W
Circle Of Confusion             : 0.011 mm
Field Of View                   : 73.7 deg
Focal Length                    : 8.8 mm (35 mm equivalent: 24.0 mm)
GPS Position                    : 49 deg 19' 47.91" N, 113 deg 10' 4.89" W
Hyperfocal Distance             : 1.41 m
Light Value                     : 13.0

Nov 2 2021- Update--RSME Error Calculation. Two regions of interest each with 3 overlapping surfaces. 100 Random Points generated within and sampled. RSME calculated between each of the surfaces.

Region of Interest 1 DEM 1 and DEM 2 : RSME is 49.76628 or approximately 4% of maximum and minimum value. DEM 2 and DEM 3 : RSME is 59.70043 or approximately 5.2% of maximum and minimum range value DEM 3 and DEM 4 : RSME is 9.934655 or approximately 0.8% of maximum and minimum range value.

Region of Interest 2

DEM 2 and 3 : RSME is 58.89464 or approximately 5% of maximum and minimum range value DEM 3 and 4 : RSME is 74.43067 or approximately 6.5% of maximum and minimum range value DEM 2 and 4 : RSME is 15.5405 or approximately 1.4% of maximum and minimum range value.

Improve this question
11
  • Can you clarify? Are you saying that for location X1, Y1 (a location where all four surfaces overlap) there is a difference in the Z values that you want to correct for? Or you are worried about the ranges of the surfaces? Since these appear to be different extents you would expect different ranges (for example, one captured a house that one did not). Finally a caution, the GNSS unit is going to return Z in a WGS84 ellipsoid vertical datum. That may not match whatever it is you are trying to compare to.
    – GBG
    Commented Oct 29, 2021 at 18:26
  • Yes for location X1, Y1 there is a difference in Z values. I think this is because it was collected with a DJI Phantom 4 drone and therefore the vertical accuracy was not great (although internally consistent). It was a fairly flat surface so the range change being off 50-70 m per a given spot between flights doesn't make sense. Would it make sense to change these into a relative change scale and stitch them together?
    – Bill_BIlliams
    Commented Nov 1, 2021 at 16:58
  • No, you would not see a 50-70 meter GNSS difference in z values of the same area from different flights. The P4P will store both the WGS84 GNSS heights as well as the height above the takeoff. How did you process these surfaces?
    – GBG
    Commented Nov 1, 2021 at 20:00
  • All four drone flights were done at 80 m AGL using drone deploy. I took the images off the P4P's SD card and separated them into different folders for each flight. In ArcGIS Pro, I had created 4 different orthomapping instances. Block adjustment. DEM creation using extended terrain matching.
    – Bill_BIlliams
    Commented Nov 1, 2021 at 22:01
  • Can you use something like EXIF tools, or GDAL_info, and post the results from the geotagged portions of the EXIF data? Do this for some images that are from the same area but contributed to surfaces that have different z values.
    – GBG
    Commented Nov 1, 2021 at 22:31

1 Answer 1

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1

You can apply a raster function to the particular DEMs in your mosaic. So for example if one of your rasters has a 2m offset the function could add or take away 2m.

You can use the Raster Item Explorer to drill down to the individual images and then add a raster function, so for a simple addition of 2m you would use the Plus function.

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