Georeference Auto-Register

Landsat 5 image acquired during the 2009 growing season over an area in southeast Nebraska, displayed in false color with Band 7 = Red, Band 4 = Green, and Band 2 = Blue to produce an "infragreen" image. The image is 8,201 columns by 7101 lines with a cell size of 30 meters. The four corner control points produced from the georeference supplied with the image are also shown.

Global Landsat 742 Google/Bing Maps tileset accessed in the Georeference process via the web from microimages.com. The yellow box shows the approximate area covered by the Landsat 5 scene. This reference tileset of global land areas was constructed from false color pan-sharpened Landsat imagery with a cell size of 14.25 meters provided by NASA. All TNTmips users can access this tileset on-line from microimages.com to use as a reference layer for displaying, georeferencing, or editing their local geodata.

Auto-Register produced 1740 control points. Using smaller Generated Point Spacing and/or larger Maximum Point Residual values would produce more control points.

Auto-Register Settings:
Match green spectral component in each RGB image:
Input Display Green --> Reference Display Green
Initial Accuracy Estimate: 5 cells
Generated Point Spacing: 100 cells
Maximum Point Residual: 2.0 cell
Correlation Patch Size: 128
Maximum Adaptive Model: As Specified (Affine)

RMS Residuals:
X = 0.27 cells, Y = 0.31 cells,
XY = 0.41 cells, (Model = Affine)

Mean Absolute Residuals:
X = 0.20 cells, Y = 0.24 cells

SPOT 5 image (4 bands) acquired during the 2009 growing season over an area in southeast Nebraska, displayed with three bands to produce a color-infrared image. The image is 6,000 columns by 6000 lines with a cell size of 10.2 meters. The four corner control points produced from the georeference supplied with the image yield RMS residuals X = 11.46 cells, Y = 1.53 cells, XY = 11.46 cells using the Affine model.

Mosaic of USDA NAIP 2009 natural color orthoimages (1-meter resolution) which has been resampled to a cell size of 4 meter. The yellow box shows the area covered by the SPOT 5 scene. The dimensions of the mosaic are 33,562 columns by 24,908 rows. When overlaid on this reference, portions of the SPOT scene with its original georeference are offset by 200 to 300 meters (20 to 30 image cells) from their correct locations. These features register to within 1 SPOT image cell after Auto-Register.

Auto-Register Settings:
Match green spectral component in each RGB image:
Input Display "Blue" --> Reference Display "Green"
Initial Accuracy Estimate: 20 cells
Generated Point Spacing: 75 cells
Maximum Point Residual: 1.0 cell
Correlation Patch Size: 128
Maximum Adaptive Model: Order 2 Polynomial

Auto-Register produced 800 control points
Using smaller Generated Point Spacing and/or larger Maximum Point Residual values would produce more control points

Auto-register compared residuals using different models and found a significant improvement using the Order 2 Polynomial model, which was set for the output points.

RMS Residuals:
X = 0.64 cells, Y = 0.60 cells, XY = 0.88 cells
(Model = Order 2 Polynomial)

Mean Absolute Residuals:
X = 0.49 cells, Y = 0.44 cells

Color-infrared aerial photo of Clarkfield, Minnesota and surroundings acquired 13 May 1991 by the National Aerial Photography Program (NAPP). Scan of photo (5418 columns by 5435 lines) has a cell size of 1.7 meters. Many agricultural fields are still bare in this early-season photo and show the gray-toned soils characteristic of southwest Minnesota. The four manually-placed control points (yellow) yield RMS residuals X = 1.90 cells, Y = 3.10 cells, XY = 3.64 cells using the Affine model.

Portion of USDA NAIP 2010 natural-color orthoimage mosaic of Yellowtail County, Minnesota (MrSID file) with cell size of 1 meter. The yellow box shows the approximate area covered by the aerial photo. The images in this orthoimage mosaic appear to have been acquired somewhat later in the growing season than the input photo. Many field boundaries are also different in the two images.