Managing Raster Graphics
DigFindR manages raster graphics using several tools:
- LiteCAD's Image Handler
- The Property Window
- World File routines
- Image Frames
All of these tools, aside from the Property Window are accessible via the Imagery Menu.
Raster graphics are images made from pixels, with those pixels having rectangular form, and portrayed by the computer through its screen or printer. The computer screen is composed of pixels displayed in a raster, or an X and Y grid structure if you like. There are many types of raster graphics, however the ones most common are the JPG, TIF, BMP and PNG types. The higher the density of the pixels, the more appreciable the quality of the image to the human eye. The higher the density the larger the file size in bytes, and the larger the file size, the longer it might take to load the image and move it around in the CAD's memory. The purpose of the map will generally dictate the density of the images used in it.
The raster graphic entity has several properties that are managed by DigFindR which include the overall size of the image in the X and Y plane, the transparency of the image, and the geographic area covered by the image. Most importantly, the squareness of the pixels in the image is controlled by DigFindR as well. To match aerial photography, which is basically a rectangle of pixels, to world coordinate space portrayed by the drawing/map, the dimension management of the raster in X and Y is usually required. This is known as the "aspect ratio".
There are some specialized raster graphics used in map making, which have the capacity to store many pixels in a highly condensed form. These images are identified by their raster compression schemes and two of these types, the ECW and the JP2 can be used by DigFindR. ECW stands for Enhanced Compression Wavelet, and JP2 stands for JPEG2000. DigFindR can make use of both of these file types.
Aside from the two previously mentioned special types, DigFindR is equipped to manage the following raster graphic types:
- BMP files
- Dr. Halo CUT files
- DDS files
- EXR files
- Raw Fax G3 files
- GIF files
- HDR files
- ICO files
- IFF files
- JNG files
- JPEG/JIF files
- JPEG-XR files
- KOALA files
- Kodak PhotoCD files
- MNG files
- PCX files
- PBM/PGM/PPM files
- PFM files
- PNG files
- Macintosh PICT files
- Photoshop PSD files
- RAW camera files
- Sun RAS files
- SGI files
- TARGA files
- TIFF files
- WBMP files
- WebP files
- XBM files
- XPM files
While it's handy to have access to all these raster graphic types, you will seldom use any of them except for JPEG and TIFF. JPEG stands for Joint Photo Expert Group, and TIFF stands for Tagged Interchange Format File. Normally the filename extensions will be .jpg and .tif.
Be aware that DigFindR is not an image processor. While it can export imagery via snapshots of its screen, it is not capable of managing pixel values such as color, hue, and masking. Nor can you crop raster graphics using DigFindR. That needs to be done using other software.