MicroStation V8 Raster Manager technology offers new options for working with raster files.
MicroStation V8 offers several changes in how raster images are handled. Raster Manager preferences have been added to the MicroStation menu under Workspace > Preferences. This change provides increased flexibility, since the Raster Manager preferences are stored within the User Preference file.
Figure 1. Raster Manager Preferences dialog. To display the Raster Manager Preferences for the current workspace, highlight the Raster Manager category in Workspace Preferences (Figure 1).
One benefit of storing the preferences with the workspace is that it is now possible to have a Workspace designated for English and another for Metric GeoTIFF and WorldFile default units.
Raster Manager preferences, with explanations for each, are listed below:
Display border around selected rasterThis option will display a dashed border around the active image. The border can also be controlled with the following key-ins:IMGMANAGER VIEWBORDER SETONIMGMANAGER VIEWBORDER SETOFF
File Georeference has priority when raster is loadedThe file Georeference information has priority over the raster reference attachment placement when this preference is toggled.
Save location Info in sister file if requiredIf this preference is toggled, Raster Manager will save the file location information into a HGR or WorldFile. HGR and WorldFiles are ASCII files that store information about the image including the origin, pixel size and rotation. The default sister type is stored in the user preference file.
The type of WorldFile can be specified using the following key-ins:RASTER DEFAULTSISTERTYPE GETRASTER DEFAULTSISTERTYPE HGRRASTER DEFAULTSISTERTYPE WORLD
Open raster files read-onlyWhen toggled, images are opened in read-only mode and cannot be modified. This preference makes it possible for the same image to be displayed multiple times within the same design file in different locations. When an image is opened read only, it also allows multiple users to share the same design file.
The following key-ins are available for this setting:RASTER OPENREADONLY SETONRASTER OPENREADONLY SETOFF
Update MS_RFDIR automatically for raster attachmentsWhen selected, this preference will append the path of the attached raster image to the MS_RFDIR configuration variable. When the path is saved within the MS_RFDIR, MicroStation will search for the raster attachments in the directories listed in this variable. These paths are stored with in the user configuration file.
This preference can be retrieved and set using the following key-ins:RASTER AUTOUPDATEREFPATH SETONRASTER AUTOUPDATEREFPATH SETOFF
Opening GeoTIFF files
Figure 2. GeoTIFF and WorldFile default units. When opening a raster image that contains a GeoTIFF header, coordinate units are essential to place the image in the correct location within the design. When opened with Raster Manager the coordinates within the header file are interpreted based on the GeoCoding Projected Coordinate System (PCS), and a table based on the European Petroleum Survey Group (EPSG) Standards. Some GeoTIFFs contain ProjLinearUnitsGeokey, which also defines the unit for the GeoTIFF. Use unit definition Geokey if present (override PCS unit)When toggled, Raster Manager will open the image using the ProjLinearUnitsGeokey, overriding the value defined by the GeoCoding Projected Coordinate System (PCS), and the European Petroleum Survey Group (EPSG) Standards.
GeoTIFF default unit labelThis option defines the unit of measure in which the GeoTIFF header is written. This is extremely important in the placement of GeoTIFF images.
WorldFile default unit labelDefines the unit of measure in which the WorldFile is written.
Raster Manager uses the unit labels to convert the numbers within the GeoTIFF header or the WorldFile to the same unit as the working units, to ensure proper placement of the image. For example, a GeoTIFF or WorldFile that is written in feet will open in the correct location in a DGN with working units set to meters or feet, by specifying the unit of measure (FT) in the default unit label.
Please note that if your image has both a GeoTIFF header and a WorldFile, the GeoTIFF header file will be used to place the image.
Figure 3. Attach Raster Reference File dialog. Recent files list contains __ filesControls the number of files displayed in the Recent Files list of the Attach Raster Reference dialog's File menu. In Figure 3, the recent file list is set to 4.
Raster Manager preferences need to be set prior to opening raster images. If the raster image does not open in the correct location, make sure your working units are set properly. If you are working with a GeoTIFF or a WorldFile and your image is opening in the wrong location, make sure the "File Georeference has Priority when the Raster is Loaded'" preference is toggled, and be sure to change the default unit in the preferences. Save the settings and then reattach your image.