Appendices

These appendices include useful background information for this workflow not included in previous topics.

Example XML file for georeferencing nonrectified images

The text below provides an example of the XML file required to perform a projective transformation for georeferencing a nonrectified image. This text could be used as a template and saved as <filename>.aux.xml, with unique coordinates required for each image file, presumably to be edited and saved through a batch process you will have to develop.

The coordinates are stored in the tags labeled <SourceGCPs> and <TargetGCPs>. The coordinate pairs represent the upper-left, upper-right, lower-left, and lower-right corners of the image file, respectively (in image space or simple pixel coordinates)—in this case, for an image 1,453 columns (x) by 1,921 rows (y) in the <SourceGCPs>, followed by corresponding longitude (x) and latitude (y) values in GCS_WGS_1984 coordinates.

Note:

Some attributes listed in the <Metadata> fields may need to be modified based on your input images.

An example of .aux.xml that contains metadata fields and attributes to perform a projective transformation for georeferencing a nonrectified image.

<PAMDataset>
  <Metadata domain="IMAGE_STRUCTURE">
    <MDI key="SOURCE_COLOR_SPACE">YCbCr</MDI>
    <MDI key="INTERLEAVE">PIXEL</MDI>
    <MDI key="COMPRESSION">JPEG</MDI>
  </Metadata>
  <Metadata domain="Esri">
    <MDI key="PyramidResamplingType">NEAREST</MDI>
  </Metadata>
  <Metadata domain="xml:ESRI" format="xml">
    <GeodataXform xsi:type="typens:ProjectiveXform" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:typens="http://www.esri.com/schemas/ArcGIS/10.1">
      <SpatialReference xsi:type="typens:GeographicCoordinateSystem">
<WKT>GEOGCS[&quot;GCS_WGS_1984&quot;,DATUM[&quot;D_WGS_1984&quot;,SPHEROID[&quot;WGS_1984&quot;,6378137.0,298.257223563]],PRIMEM[&quot;Greenwich&quot;,0.0],UNIT[&quot;Degree&quot;,0.0174532925199433],AUTHORITY[&quot;EPSG&quot;,4326]]</WKT>
        <XOrigin>-400</XOrigin>
        <YOrigin>-400</YOrigin>
        <XYScale>11258999068426.24</XYScale>
        <ZOrigin>-100000</ZOrigin>
        <ZScale>10000</ZScale>
        <MOrigin>-100000</MOrigin>
        <MScale>10000</MScale>
        <XYTolerance>8.983152841195215e-009</XYTolerance>
        <ZTolerance>0.001</ZTolerance>
        <MTolerance>0.001</MTolerance>
        <HighPrecision>true</HighPrecision>
        <LeftLongitude>-180</LeftLongitude>
        <WKID>4326</WKID>
        <LatestWKID>4326</LatestWKID>
      </SpatialReference>
      <SourceGCPs xsi:type="typens:ArrayOfDouble">
        <Double>0.0</Double>
        <Double>0.0</Double>
        <Double>1452.0</Double>
        <Double>0.0</Double>
        <Double>0.0</Double>
        <Double>-1920.0</Double>
        <Double>1452.0</Double>
        <Double>-1920.0</Double>
      </SourceGCPs>
      <TargetGCPs xsi:type="typens:ArrayOfDouble">
        <Double>-122.62817879281903</Double>
        <Double>45.636684801338085</Double>
        <Double>-122.61170102535365</Double>
        <Double>45.636407197554092</Double>
        <Double>-122.62919006374651</Double>
        <Double>45.614635129350745</Double>
        <Double>-122.61134410620278</Double>
        <Double>45.614278210199871</Double>
      </TargetGCPs>
    </GeodataXform>
  </Metadata>
</PAMDataset>