AZ_PROJ.FAQ released with AZ_PROJ v1.1 1. Is it possible to fill states/countries/islands with colors? The short answer is possibly. The .wdb files contain geographic information in the form of a series of points (given in lat/lon) which are joined by az_proj to make a map-line (also called wdb path). The wdb file consists of series of these map lines each of 30-500 points. Postscript can fill areas bound by such lines if they form a closed path. The original map-lines in the .wdb files are not closed loops. However Paul Anderson has edited the files into closed loops and are used in the *.wdb files now. I would need to decide on a colour scheme and a method of implementing it, if there was sufficient interest. The wdb pathes for the large lakes have all been edited by hand, so that the lakes can be filled (with blue). The maximum number of points in a postscript path is somewhat less than 1500 (depending on what else is sitting in memory). Except for simple paths like state borders, most continents etc are made up of more that 1500 points. 2) Why do the bright colors on the display (like light blue for lakes) become darker on a color printer (like murky grey blue)? This is because of the different conventions used for RGB on a display and a printer. Printers are linear devices. You give it G=0.25 and the print reflects 75% of the green (and 100% of everything else). A display doesn't absorb or reflect anything. Instead light comes from the screen, an amount which is non-linear in photons/grid voltage (or some control function). Since all phoshors are about the same as each other, there were no great compatibility problems between different TV screens and no-one really cared about the non-linearity. However you can't run a printer or display off the control signals designed for the other type of device, without doing the conversion (called a "gamma" correction). Postscript does not ask the device it is running on whether it is a printer or a display, so other subtle ruses have been devised in az_proj to handle the situation. We've assumed that the output is to a display. Postscript can ask the "product" it's running on, and the product will return a string (eg nothing, Deskjet550C). If the string matches a known printer (we know Deskjet550C, 1200C or Apple Phase IISDX), then we do the gamma correction. If your printer is another color printer, then follow the instructions in az_proj.ps for detecting your printer (you'll have to duplicate a few lines and put in your string). Look for the string "gamma" in the code to locate the place to start changing things. 3). Can I spread my map over several piece of paper, and later tape/staple/glue them together to make a bigger map? Yes. For further details, see the center_offset feature in az_ini.ps. You choose the center of the projection (your QTH), and make a map to fill one page. If you now want to make a 4 page map, divide the 1 page map into 4 quadrants, and find the lat/lon of the center of each quadrant. Now change the scale by a factor of 2, then make 4 maps. For each map choose to offset the center of the page (not the center of the projection) to the lat/lon of the center of the 4 quadrants of the one page map. 4) Where's the .exe file? Some of you ask me. The answer is that there's _NO_ .exe file in the AZ_PROJ package. The package consists of a set of files which when sent to a Postscript printer will produce a map of your choice. The files are all Postscript, which is ascii and can be edited by a normal programming editor i.e. an ascii editor. You do not send *.exe files to printers. If you want to use these files to create maps on your monitor, or to print to a non-Postscript printer, then you need to find a Postscript Interpreter that will make allow you to do this. This interpreter will be different for different operating systems. Ghostscript (see elsewhere in this file) does a good job of this for DOS, Win, DVX, OS/2, Unix and this is what we used. There are other programs that do the same job, that I have not tested with AZ_PROJ. So the answer is that _you_ have to supply the .exe file (the Postscript interpreter) or else a Postscript printer. (For information on getting Ghostscript, see the README.AZP file or ghost.doc). Joe NA3T Mar 2000