The purpose of this exercise is to get MicroStation to automatically scale and position a USGS quad sheet image when it is imported into a design file (commonly referred to as geo-referencing the quad sheet image). Although the quad sheet image may be viewed in MicroStation using other means, this is the only procedure that will automatically geo-reference the quad sheet.

MicroStation Image Manager must be installed on your PC in order to do the procedure outlined here and also on any PC where the dgn with quad sheet is going to be viewed. If Image Manager... isn't one of the options in the MicroStation File pulldown menu, then you don't have Image Manager installed and you can't do this procedure.

When the quad sheet data is downloaded from the USGS web site you get a zip file containing several (probably three) files. As a minimum, there should be

1. a .TIF file (the quad sheet raster image), and
2. a .TFW file (the location/scaling information for the quad sheet image, referred to as the world file)

1. Open the TIFF world file (*.tfw) in Notepad. You should see something similar to the example shown below.

   

2. Make note of the last two lines in the world file. These are the East and North coordinates, respectively, of the upper left corner of the quad sheet image. (Technically the coordinates of the upper right corner of the quad sheet are what we're interested in, but in practice the upper left corner coordinates are close enough.)

3. The maximum coordinate value that will fit on the standard dgn file design plane is approx. 4,295,000 for both North and East coordinates.
   • If both the maximum North and East UTM coordinates for the quad sheet are less than 4,295,000 then the quad sheet will fit in the standard dgn file and you can skip the remainder of this section.
   • If the maximum North and/or East UTM coordinates for the quad sheet are greater than 4,295,000 then the global origin of the dgn file will have to be adjusted to allow the quad sheet to fit on the design plane.
   Notice for the example shown above the East coordinate (518,911) will easily fit in the standard dgn file (i.e., 518,911 << 4,295,000), but the North coordinate (4,942,062) will not fit in the standard dgn file (i.e., 4,942,062 > 4,295,000).

4. Calculate how far the global origin needs to be shifted in order to fit the quad sheet on the design plane. Use EastOffset and NorthOffset to denote the distance the global origin needs to be shifted.
   • When a maximum coordinate value is less than 4,295,000 then that the global origin doesn't need to be adjusted in that direction (i.e., the adjustment is 0). For the example shown above the maximum East coordinate is less than 4,295,000 so no adjustment is required in the East direction; EastOffset would be 0 in this case.
   • When the maximum coordinate value is greater than 4,295,000 then the global origin needs to be shifted for that direction. For the example shown above the maximum North coordinate is greater than 4,295,000 and therefore the global origin needs to be adjusted to fit on the design plane. The absolute minimum distance the global origin needs to be shifted is equal to the maximum North coordinate for the quad sheet minus 4,295,000 (the maximum allowable coordinate on the standard design plane). For the example this which would be approx. 4,942,000 - 4,295,000 = 647,000. Round this number up to the next highest even million (1,000,000 in this case) and use it for the NorthOffset value.

5. Reset the global origin in the design file, if necessary. (If both coordinates fit on the standard design plane then skip this step.)
   • In the MicroStation command window key in
        go=EastOffset,NorthOffset
     where EastOffset and NorthOffset are the values calculated as outlined above. (For the example shown here the keyin would be go=0,1000000)
   • Immediately after typing in the go= command and hitting the Enter key, hit the Reset (right) mouse button. The global origin won't be reset correctly if this sequence isn't followed exactly.
   • Save the current settings in the dgn file (i.e., File > Save Settings from the MicroStation pulldown menus). The global origin won't be reset correctly if this sequence isn't followed exactly.

1. Select File > Image Manager from the MicroStation pulldown menus to bring up the Image Manager dialog box. (Note: If Image Manager isn't on the MicroStation File menu then it hasn't been loaded onto your PC.)
   
   
   

2. Select File > Open... from the Image Manager dialog pulldown menus to bring up the Open Image dialog (shown below).
   1. Change the File Type option button to All Files (*.*)
   2. Navigate to the directory where the quad sheet TIFF file is stored and select the file.
   3. The Place Interactively should not be checked.
   4. Click on the OK button to attach the quad sheet image.
   
   
   
   
3. To fit the quad sheet image to the current view use Display > Fit Images to View from the Image Manager pulldown menus.  (Shown below)

   

4. Check to be sure the quad sheet image was geo-referenced correctly.
   • Check the location of the map image by placing MicroStation tentative points at the grid tick marks around the border of the image and comparing the xy values that are reported in the MicroStation status field with the coordinates of the grid ticks.
   • Check the scale of the map image by using the MicroStation Measure Between Points to measure the distance between section lines on the map. It should be something close to 1600 meters.

• The image will display and scroll much faster, and
• the HMR file size will be roughly half the TIFF file size.

1. In the Image Manager dialog:
   1. Double click on the TIFF file name in the Image Manager file list box. The background color behind the file name should change from blue to red.
   2. Select File > Save As... from the Image Manager pulldown menus to bring up the Save As dialog box.

2. In the Save As dialog box:
   3. Key in the file name for the new HMR image in the Name: field. Normally the file name will be the same base file name as the TIFF file plus a .hmr extension.
   4. Navigate to the directory where you want to store the new HMR file.
   5. Set the Output Type: button to HMR.
   6. Set the Output Pixel Type button to 256 Colors.
   7. Set the Output Data Compression to Deflate.
   8. Click on the OK button to start the TIFF to HMR conversion.
      
      

   

3. The conversion from from TIFF to HMR format will take a minute or two. When the conversion has been completed, three things will have happened:
   1. A new HMR format version of the quad sheet is created on your hard disk,
   2. the original TIFF version will be detached by Image Manager (but not deleted from the hard disk), and
   3. the new HMR format version will be attached by Image Manager in place of the original TIFF (as shown below).
   
   
   

1. To plot images in HMR format images with Image Manager installed on your computer you need to use MicroStation Print/Plot (File > Print/Plot... from the Image Manager pulldown menus) with the plot driver file imgen.plt.( To plot HMR format images with Descartes installed on your computer, use plot driver dcgen.plt.)
2. If the quad sheet image was not converted to HMR format (i.e., it's still a TIFF file), then any Windows system plot driver (e.g., printer.plt) will work.
3. Image Manager is an optional component of MicroStation. Image Manager is included on the MicroStation installation CD, but it is not automatically loaded when MicroStation is installed. To load Image Manager when MicroStation is initially installed, select Image Manager in the Utilities section of the installation setup dialog. (You can install Image Manager on top of an existing MicroStation by doing a custom installation from the MicroStation CD and un-checking everything except Image Manager.)
4. Image Manager is a standalone version of one of several modules that make up the Descartes program. The purpose of Image Manager is to allow the user to view and plot raster images from within MicroStation. Image Manager does not have any capability to edit, transform, or register images; Descartes is the MicroStation product that has these features.
5. Having both Image Manager and Descartes loaded on the same PC will cause problems. Load one or the other but not both.
6. File > Import > Image... from the MicroStation pulldown menus will not automatically import and geo-reference either version of the TIFF file.