U.S. Department of the Interior U.S. Geological Survey Geometric Assessment of Remote Sensed Data Oct Presented By: Michael Choate, SAIC U.S. Geological Survey, National Center for EROS Sioux Falls, SD

2 Outline and Introduction Landsat 7 Image Assessment System (IAS)  Background  Expanding the use of IAS Ground Control Mensuration RESOURCESAT-1 Assessment  Statistics  Vector Plots Conclusions

3 Landsat Image Assessment System (1 of 2) Responsible for assessment of image quality of Enhanced Thematic Mapper (ETM+) Ensure compliance with radiometric and geometric requirements Perform radiometric and geometric calibration of satellite and ETM+ Calibration results and updates distributed through Calibration Parameter File (CPF) IAS contains Image to Image (I2I) registration assessment tool  Provides numerical evaluation of accuracy of common bands of temporally distinct ETM+ images  No real restriction on image data sets that can be used, other sensor can be used in assessment IAS contains Band to Band (B2B) registration assessment tool  Provides numerical evaluation of accuracy of between band registration within an image  No real restriction on image data sets that can be used, other sensor can be used in assessment

4 Landsat Image Assessment System (2 of 2) Expanding the IAS beyond ETM+  LPGS-Lite used as prototype for Advanced Land Imager (ALI) assessment system (ALIAS)  IAS I2I and B2B used for assessment of other sensors and datasets SurreySat Orbview-3 Digitized aerial photography

5 Ground Control (1 of 2) Landsat IAS built ground reference data sets called Geometric Supersites or just Supersites Built from Digital Orthophoto Quadrangulars (DOQs)  DOQs are designed to meet national mapping accuracy standards of 1:24k maps, or ~6 meters  Inspection with highly accurate GPS surveyed locations showed most DOQs exceeded 6 meters accuracy  1 meter DOQs reduced in resolution to match PAN band (15m for ETM+ and 10m for ALI)  DOQs are mosaiced to create a data set equal to one World Wide Reference 2 (WRS2) nominal swath/length  Image chips are pulled from DOQ mosaics  USGS 1 arc second DEMs used for ground control height Currently 30 data sets available

6 Ground Control (2 of 2) DOQ Mosaic Note that individual DOQ files are visible in the mosaic

7 Ground Control (3 of 3) Landsat WRS-2 Supersite Locations (CONUS)

8 Mensuration Mensuration done with Grey Scale Correlation Offset is calculated by fitting surface around peak location Outliers removed by observing correlation characteristics and residual statistics Correlation points chosen as evenly displaced points throughput image files

9 Correlation Grey Scale Correlation Calculate Peak X and Y Offset

10 RESOURCESAT-1 Payload contains three imaging sensors  Linear Imaging Self Scanner IV (LISS-IV) Ground sample distance of 5.8 meters 3 bands 70km swath (monochromatic) 23km (multispectral)  Linear Imaging Self Scanner III (LISS-III) Ground sample distance of 23.5 meters 4 bands 141km swath  Advanced Wide Field Sensor (AWiFS) Two separate sensor modules (AWiFS-A and AWiFS-B) 4 bands 370km swath for each camera (740km total)

11 RESOURCESAT-1 Assessment (1 of 2) Attempt to assess both the AWiFS and LISS-III sensors aboard the RESOURCESAT-1 platform Given two areas of coverage  Arizona Corresponds to Landsat WRS-2 path 37 row 37 Acquisition date 6/29/2005  Railroad Valley Corresponds to Landsat WRS-2 path 40 row 33 Acquisition date 8/10/2005 Both images were orthorectified geocoded products AWiFS Assessment  Image extent of AWiFS data set allowed only a very small portion of the image file to be compared to corresponding supersite Issue made worse by comparing individual AWiFS data sets (A,B,C,D) independently Independent study done to avoid double resampling AWiFS data sets (each data set map projected with different set of parameters)

12 RESOURCESAT-1 Assessment (2-2) Control covered only partial amount of multiple data sets  Band assessment made for all data sets AWiFS A, B, C and D data sets assessed independently LISS-III Assessment  DOQ control completely covered full image extent Output included  residuals file containing point by point residual offset in line and sample direction  statistical file containing maximum, minimum, mean, standard deviation, and root mean squared error of residuals for line and sample directions  residuals vector plot

13 DOQ and LISS-III AWiFS-A,B,C,D Arizona Data Sets (AWiFS, LISS-III, DOQ) DOQ LISS-III m m m A B C D DOQ and LISS-III

14 Full Resolution LISS-III to DOQ DOQLISS-III

15 AWiFS Image-to-Image

16 AWiFS Band-to-band registration Arizona Rband = Reference Sband = Search StDevL = Standard deviation line StDevS = Standard deviation sample RMSEL = Root mean squared error line RMSES = Root mean squared error sample

17 AWiFS Band-to-band registration Railroad Valley Rband = Reference Sband = Search StDevL = Standard deviation line StDevS = Standard deviation sample RMSEL = Root mean squared error line RMSES = Root mean squared error sample

18 LISS-III Image-to-Image

19 LISS-III Band-to-band registration Arizona Railroad Valley Rband = Reference Sband = Search StDevL = Standard deviation line StDevS = Standard deviation sample RMSEL = Root mean squared error line RMSES = Root mean squared error sample

20 LISS-III Band registration vector plot(Arizona) Vectors scaled to show trend

21 LISS-III Band registration vector plot (Railroad Valley) Vectors scaled to show trend

22 LISS-III Image to Image Residuals (Arizona) Vectors scaled by 350 LISS-III Arizona Data set Vector residuals comparing LISS-III to DOQs

23 LISS-III Image to Image Residuals (Railroad Valley) Vectors scaled by 350 LISS-III Railroad Valley Data Set Vector Residual Comparing LISS-III and DOQs

24 Conclusions Landat 7 Image Assessment System can be expanded for use beyond that of the Enhanced Thematic Mapper Image extent of AWiFS data set difficult to assess with given ground control available  Approach using other type of control covering more area would work better Mosaicing several Landsat scenes National Land Cover Database (NLCD) AWiFS data set band registration difficult to assess, more data sets would be helpful LISS-III data sets showed good relative geometric accuracy to that of DOQs LISS-III vector plots for band registration residuals show possibility of small misalignment

25 Back Up Slides

26 LISS-III Band registration vector plot (Arizona)

27 AWiFS Railroad Valley Data Set Showing DOQ Coverage DOQ Coverage Red out line is equal to approximately one Landsat WRS image extent

28 LISS-III Railroad Valley Data Set Showing DOQ Coverage LISS-III DOQ Mosaic