Registering Images with WMS

There are many times when you will want to display an image in WMS.  You may want to digitize features from a scanned map or digitize contour lines to create a TIN.  You may want to overlay your watershed boundaries onto a  map, or you can use the image for presentation purposes.

A GEOTIFF is a special type of TIFF image which already contains the registration information within the image itself, and is registered (or georeferenced) automatically when imported in WMS.  All other images must be registered manually when imported into WMS.  When importing an image into WMS, two possibilities exist:

Case I: You can manually register any scanned image.  This could be an image you scanned yourself, or one obtained elsewhere.
Case II: You can register an image with a TIFF world file, if you have one.
 

Case I

In order to manually register the image properly, you must identify three points on the map in which the real-world coordinates are known (e.g., latitude and longitude).  The coordinates must be in a planimetric coordinate system such as UTM or another (x,y) coordinate system.  If the coordinates are in latitude/longitude, then you will need convert them to a planimetric coordinate system (WMS offers a utility which converts latitude/longitude coordinates to UTM NAD27).

  1. Obtain a TIFF or JPEG image, or scan one yourself,
    Note: If using a TIFF image, then be aware that WMS only supports *.tif files that are either uncompressed, or compressed with the Packbits option,

  2. Start WMS,

  3. Select Import from the File pulldown menu,

  4. Select "TIFF File (*.tif)" or "JPEG Image File (*.jpg, *.jpeg)" from the Files of Type list,

  5. Find and open your TIFF or JPG image.  The Register Image dialog should now be open with your image displayed in it (see figure below),

  6. Starting with any one of the known points, enter in the (U,V) pixel coordinates,
    This can also be done by dragging any one of the three red crosshairs (the ones with the numbers next to them) to the approximate location of the known point on the image.  Then zoom in over the point and place the red register crosshair exactly over the known point.  As you do this, the (U,V) pixel coordinates will change automatically.

  7. Now enter the corresponding real-world coordinates for the point,
    For example, if the coordinates of the point were x = 505,241 and y = 4,245,231, then you would enter "505241" for X and "4245231" for Y in their respective boxes.  If your real-world coordinates are in latitude/longitude, then you can convert them to a UTM NAD27 coordinate system by clicking on the Lat/Long -> UTM button.

  8. Repeat the previous two steps for the other two points,
    You can use the Frame Image macro  to zoom out to the entire image again.

  9. Click OK.  
    You've have now successfully registered the image.
                                           


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Case II

Some images have already been registered through the use of separate file called a world file.  The naming convention for an image file's world file is to take the first and last letters of the files original extension, and add a "w."  For example, in the case of TIFF images (*.tif), the TIFF world file has the extension ".tfw", a JPEG image (*.jpg) world file has the extension ".jgw," a BMP image (*.bmp) world file has the extension ".bpw," etc.  It is a good practice to give the image file and its world file the same filename prefix.  For example, you might have a TIFF image called canyon.tiff and a TIFF world file called canyon.tfw .  The world file contains the registration information for the image and can be read directly into  WMS.

  1. Obtain the image and the image's world file.

  2. Start WMS.

  3. Select Import from the File

    pull-down menu.

  4. Select "TIFF Files (*.tif)" or "JPEG Image Files (*.jpg, *.jpeg) from Files of Type list,

  5. Find and open your image.  The Register Image dialog should now be open with your image displayed in it (see figure below).

  6. Click the Import World File button near the bottom.

  7. Find and open the world file   You will notice that the red crosshairs (the ones with the numbers next to them) automatically move and the X, Y, U, and V coordinates are automatically filled in.

  8. Select OK to register the image.
                                   

 

 

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