Method

*Each screenshot is a link to the larger full-resolution image*

*All steps are documented in the MICRODEM Help file*

1. Digitize maps

The first step was to translate the historical map into a format the computer could understand.  Using a scanned VII Corps historical map from Prof. Guth, we compared these locations with present-day NGA Gazeteers of France, Germany and Belgium.  This enabled us to use WGS84 coordinates to lay down an accurate grid atop the scanned projection, from which we were then able to record the data.

2. Record locations of units

Using MICRODEM, we created a shapefile for each of the VII Corps units and recorded their position over the course of the twelve-month period covered on the map.  This was accomplished by simply pointing and clicking on wherever the unit was located on that particular day, as indicated by the master timeline along the bottom of the image.

3. Download unit patches

Once we determined which units to digitize and then recorded their positions, the next step was to identify them with their respective unit crest or patch.  This makes the data readily distinguishable when present in Google Earth, as well as helping to preserve the historical aspect of our project.  The patches were easily obtained by a Google search, then reduced in size for concurrent display on the map.

4. Create unit symbols

Another method to represent our data is by using the technical military symbol for the units, as was used on the original situation map.  This was accomplished using the military icon generator option of MICRODEM, and installing a third-party set of military icons from the Internet.  The icon generator is a dialog-box GUI base, and allows options such as the designation and size of the unit to be set before exporting the image.

5. Bring everything into the database (edit with Microsoft Excel)

Combining the shapefile position data with the unit icons and patches, we then searched for each individual historical website and corresponding images for the units displayed.  These parameters were written with reference to the local directories where the images were stored, which later on MICRODEM converted to links.  When taken into MICRODEM, these column headings become export options for the results file.

• Within the record box in Google Earth, we have the option to display text, an image, and a hyperlink, all options which we initially filled out in Microsoft Excel.  Each individual data point displayed in Google Earth is clickable, bringing up a dialog box that displays particular information about that individual record.

• The image displayed in each individual record is of smaller dimensions and referenced from the original file.  When clicked, the image will load at full resolution in your browser window.  All nine historical images used were downloaded from the US Library of Congress, and depict various scenes throughout the war.

6. Set parameters of MICRODEM to produce desired output

Once a database has been loaded on the map, MICRODEM provides the option to export the results onto either Google Maps or into Google Earth.  Using the parameters of this dialog box, we customized the KML files for each of the units recorded, then grouped them together into one common US Army VII Corps file to display simultaneously.

7. Publish

The results of the work as shown in Google Earth, depicting unit patches across the entire time frame recorded for the project.

Situation Maps

Prof. Guth discovered a section of the Library of Congress website that has scanned daily situational maps from the area and time period we were studying for the project.  As such, we were able to obtain and register a series of twelve of these maps, one per month for the year observed, and then combine them with our unit position data displayed in Google Earth.

The maps were originally provided in the MrSID imagery format, which is a large compression ratio that then offers you several different resolutions for uncompressing.  We chose the medium resolution, producing a file of approximately 17MB for ease of portability and downloading.  Once saved as our base image, each map then needed to have a lat/long grid associated with corresponding intersection points.  First, we registered the corners of the image, then went back and identified each intersection of lines of latitude and longitude for reference from the corners.  Then using the TIN registration option, the maps were registered and re-projected into Google Earth as a series of tiles associated with their corresponding KML files.  We then saved these as stand-alone KMZ archives.