Triton TritonMap - Manual (Page 57)

June 2004 DelphMap™ User's Manual
In order to position any bitmap correctly in a project, your file to be imported
must contain the information shown in Table 1.
TABLE 1. Info that must exist in an importable background file
Parameter Discussion
the
coordinates of
the N-W
corner of the
bitmap in grid
units This information must be present either as Lat/Long or as a grid
coordinate, if the position is in Lat/Long then you could use TEI
GeoCalc to convert to a grid position that matches the projection
information for your DelphMap project. If the position is already in
grid coordinates, then you must have the projection information for
those coordinates.
the N-S and
E-W
dimensions of
the bitmap in
grid units If you don’t know what the dimensions are, you may be able to
calculate them if you know the resolution and the size of the image
in pixels. To find the size of an image in pixels, you can open it in a
number of different “Paint” type programs and look at the statistics
or properties associated with the image. Or simply use the
Windows Explorer (file manager) to get the information: Right-click
the file name, choose Properties, and click the Sum_mary tab.
The image’s dimensions, in pixels, are displayed there.
the coordinate
system
(projection)
that was used You have this information if the upper left corner coordinates are in
grid. If the coordinate system is specified as latitude and longitude,
then you need to calculate the equivalent values for the grid
system using TEI GeoCalc; after calculating, you can then specify
whatever projection you need.
3. Optional: If you wish to seamlessly blend the unused edges of
your background image with whatever background color is
present in your DelphMap working window, put a check mark in
the Use a transparency color box and choose the same color
as the unused edges (usually white). When you do that, the
borders of the background image will merge with whatever
background color you have in DelphMap’s working window.
Chapter 3: Importing and Exporting 43