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M A P V I E W 2.0 Gisbert W. Selke, 11 Jan 1989 MapView is an interactive programme for drawing maps in a variety of projections. It reads data from files in a number of formats and displays them on all display adapters supported by TurboPascal 5.0, the language it was written in. It should run on all IBM PCs and clones on which TurboPascal's Graph unit runs. As distributed, it makes no use of a coprocessor, but it can easily be recompiled to do so. It makes nearly no sense to use this programme without a hard disk. A hardcopy facility is built in which is designed for Epson type dot matrix printers. Also supplied are two programmes to preprocess data (Mp1ToMpx, TrigCalc) and two to view previously generated pictures (Slide/QSlide). Full sources to all the programmes are supplied. - Map data files have to be acquired independently; MapView has no built-in data whatsoever. The map files it was designed to work with have been produced by John Allison and can probably gotten at the same place (bulletin board etc.) as MapView. (i) Quick start --------------- This tells you how to get started as fast as possible. All the refinements, structuring, and so forth, will be discussed later. - So, first, put all the MapView-related files into one subdirectory for now (you may omit the PAS and TPU files); put all the MP1 files you must have received independently there, too. Start up MapView from the DOS prompt; after marvelling at the logo, hit "X", followed by "ECL" when prompted (always without the quotes, to be sure; case is insignificant, by the way). Don't be bothered by a message saying that some file E0.LST can't be found - MapView is just showing off its ability to find even things that are not there. Hopefully, you will now watch a map of Europe (continental outlines only) being drawn. (Later you will learn how to make drawing much faster.) Now type "W" - you will see a pair of crosshairs, which you can move with the cursor keys; the upper left corner of the screen will always tell you where you are. When you're tired of it, hit the <ENTER> key. Now type "X" again, then "EN". You will have a different kind of map now, and this time it will be Europe along with its islands, lakes, and political boundaries. When drawing has finished, type "Z" to zoom in; first use the cursor keys to designate the South-West corner, hit <ENTER>, then designate the North-East corner, hit <ENTER> again. Nothing will happen. But then, hit "E" to erase the screen, then "D" to redraw - now you'll get the part you picked. Hit "X" again, then "WORLD0". Now you'll get a view of the Earth as seen from outer space; this will take some time to do. When you're ready to proceed, hit "S": you have just created a picture file on disk. Experiment some more; get help with "?", display settings with "M",... and finally, hit "Q" to quit. You're not through, yet - at the DOS prompt, type "SLIDE SCREEN /R0". In an instant, the world map will pop up on the screen. If you have typed "S" more often during your first session, all the pictures you saved will be shown in an endless slide show. Hit any key to finish. (You might also try the same with QSlide, if you have a CGA or a Hercules.) You're done for now! (ii) Setup ---------- You will need at least MAPVIEW.EXE and a couple of map files (with extensions .MP3, .MP2, .MP0, or .MP1, see (vii) below); also, you will need the Borland BGI driver applicable to your display adapter. If you want the simple on-line help screen to be available, you need MAPVIEW.HLP. In addition, you may want to have MAPVIEW.CNF (a configuration file in plain text format, see (v) below), SLIDE.EXE and/or QSLIDE.EXE to view previously generated pictures as a 'slide show', and a variety of list files (extension .LST) and command files (extension .CMD). For the generation of .MP2 or .MP0 files, you will also need MP1TOMPX.EXE. TRIGCALC.EXE will prepare a file with precomputed trigonometric values for fastest execution; this is especially useful with MP0 or MP1 files but also speeds up use of MP2 and MP3 files somewhat. I suggest you create a directory WORLDMAP to hold the executables, a subdirectory each for the command and list files (and possibly one for the picture files you will generate), and group the map files into subdirectories according to continents, say, EUROPE, AUSTRALI, and so forth. This is for your convenience only, though; MapView doesn't make any assumptions on your directory structure except that MAPVIEW.CNF, if present, MAPVIEW.HLP, and the BGI driver be in the current directory (or accessible via APPEND or the like). If you create subdirectories, you should set up MAPVIEW.CNF to reflect your choices; you can set a few other esoteric things in this file, too (see (v) below). If you want to pre-process the map files either to save disk space or to make execution much faster - which I recommend -, put all the map files into one directory, then use Mp1ToMpx (see (vii) below); move the resulting MP0, MP2 or MP3 files into the appropriate subdirectories, finally deleting the raw MP1 files. (You do have a back-up copy, don't you?). Finally, run TrigCalc if you have some 108KB to spare; see the note on timings (appendix C below) to decide if the speed gain is worth the disk space expenditure. - Now you may remove MP1TOMPX.EXE and TRIGCALC.EXE. Nearly all of this can be automated by using the two batch files supplied, INSTMVU.BAT and INSTMAP.BAT, which will set up everything for use with the configuration file provided. Copy all the MapView files and all the map files into a directory of your choosing, say WORLDMAP. Then type "INSTMVU": this will create several subdirectories for use by MapView and move the appropriate files to their places. Then type "INSTMAP 2" (or "INSTMAP 3" if you have an 80x87 coprocessor and are willing to recompile MapView): this will preprocess all the map files for fastest MapView operation and place them in subdirectories of their own. Alternatively, type "INSTMAP 0" if your disk space is scarce, or "INSTMAP 1", which will not preprocess files but just move them into the various subdirectories. - Note: before you start InstMap, make sure you have backup copies of the map data files as you received them - InstMap will delete these files after preprocessing them! - InstMap will take some time to run (about 45 minutes on my 10MHz AT clone if used with the "2" option; much less with the "0" option, and nearly no time with the "1" option). (iii) MapView operation ----------------------- Start MapView by typing 'MAPVIEW' at the DOS prompt. It will display its default start-up screen and show a prompt in the upper row of the graphics screen. If ever you forget what the cryptic letters up there mean, type "?" to get on-line help. Now for the commands at your command, in an order that can get you started: L - set file List MapView will prompt you for the name of a file that contains the names of map files. The purpose of this is to allow you to group files together in a meaningful way, like, say E0, E1, and E2 to get Europe's outlines, its islands, and its lakes, but not its political boundaries. As an option, a list file may specify a colour for each map which then overrides any colour given by the "C" command (see below). The "L" command will not draw anything - that is done by the "D" command. List files have, by default, an extension of .LST; you may override this, though, by explicitly providing one. You can display a list of all available list files by replying "?" to the file name prompt. - As a special case, if you want to view a single map file, you may also specify this file's name here; if MapView can't find a list file with the name you give, it will try to find a map file with this name. - See (iv) below on how to prepare list files; you'll also find some intimation on why, probably, the LEV0 through LEV3 files are all you'll ever be going to need. D - Display a map Once you have specified a list file, you may draw the map files given there by this command. It uses all the parameters you have set so far (or the default ones). The screen is not erased initially (use the 'E' command for this); this allows you to overlay several maps, or maybe draw the same map with various projection methods on top of each other, to study the differences. MapView tells you with a beep when drawing is finished - it may take some time... If you get tired in the meantime, pressing a single key will suspend drawing; pressing "Q" or "ESCape" will return you to the main MapView prompt. (MapView will maybe not answer your request immediately, but it will eventually.) If you have set a small window and have specified files that have many coordinates outside your window, nothing will seem to happen for a long time; be patient. To keep you happy, there will be a small sign of progress in the lower right corner of the screen (unless you have toggled of the prompt line). P - set Projection method Since the Earth is a sphere (well, approximately) and your screen is part of a plane (well, approximately, again), MapView will have to map the surface coordinates into the plane. There is a choice of four different projections built into MapView: None (a misnomer, kept for historical reasons) simply treats the latitude and longitude as the y and x coordinates, respectively. Mercator uses a non-linear scaling which preserves angles; it is best near to the equator but distorts heavily as you approach the poles. Azimuthal here stands for an area-preserving azimuthal map, centered on one of the poles. This is a good one for regions way North or South. MapView chooses the pole that is best for the map window you have set (see "Z" below). Orthogonal projection displays the Earth as seen from outer space, and is particularly good for animated slide shows. Lambert uses a conformal conical mapping, i.e., angles are preserved locally. It is one of the better methods for smaller regions in medium latitudes. Of course, there are projection methods galore - maybe I'll add some more one day. Or maybe I won't. The latter two methods require you to specify a 'midpoint'; for the orthogonal projection, this specifies your eye-point, and for the Lambert projection, the latitude given is the one at which lengths are preserved, and the longitude implicitly defines the orientation of the map. The midpoint should, in general, be close to the center of the window you choose (see the "Z" command). You may enter these values either in decimal degrees or in dd:mm:ss form. - After startup, MapView uses Mercator projection by default. Z - Zoom, or: set map window If you want to view only part of the world, you may specify the South-West and the North-East right corners of the window you are interested in. You may give the coordinates explicitly (in decimal degrees or in dd:mm:ss form) in response to the prompt, ending each number by hitting "ENTER". Southern latitudes and Western longitudes are indicated by specifying a negative number. Alternatively, if you want to zoom in, you may use a cursor key to activate the crosshairs and choose the window graphically. Movement is pixel-wise by pressing one of the four arrow keys, or 10-pixel-wise by pressing "SHIFT" plus one of the numeric keypad arrow keys (assuming NumLock is off; on some keyboards, you may also use the "CTRL" key instead of "SHIFT"). Hit "ENTER" when you have picked the lower left corner, then pick the upper right corner in the same fashion. This will not yield the desired results if the region indicated crosses the international date line; sorry about that. Zooming will affect future "D" commands only, not the current screen. - Note that some projection methods will internally restrict the area displayed, according to the characteristics of each method. G - set Grid By default, MapView draws a grid in 20° intervals on every map. The grid width can be changed by the "G" command for latitude and longitude independently. Specifying no number toggles grid display on or off. W - Where are we now This command displays crosshairs, which can be moved with the arrow keys (or with "SHIFT" plus arrow keys for coarse movement); the coordinates corresponding to the current crosshairs location are displayed in the upper left corner. Hit "ENTER" to return to the main prompt when done. E - Erase screen MapView never erases the screen by itself - you have to tell it to do so. S - Save screen to file The screen is copied to the file you have previously specified with the "N" command (see below), or to the default file of SCREEN.PIC. Pictures are always appended at the end of the file. N - set Name of screen save file When you type "N", you will be prompted for the name of a file to save screens to. If you omit the extension, the default extension ".PIC" will be added. If you specify no drive or path, the default directory from your configuration file, if any, will be used. (If you want to override that choice and save to the current directory, start the file name with ".\".) - MapView will check if the file already exists; if so, it will append your saves to the end of the file. If not, a new file is created. - For an existing file, MapView checks whether it has a valid pic file format for the graphics adapter you are using. - The default name for screen save files is SCREEN.PIC. H - Hardcopy of screen to printer The current graphics screen is copied to the printer via one of the printer ports. This assumes the printer to be similar to an Epson FX, which many printers in fact are; if yours is not, you're out of luck, unless you adapt the source code (or persuade me to do so). - The default port used is 1 (i.e., LPT1); this can be changed in the configuration file (cf. (v) below). C - set Colour Future drawing will use the colour given by this number, except for those files that have a colour associated with them in the current list file (see (iv) below). What colour this in fact means depends on your graphics card and settings. You cannot specify a colour invalid for your graphics adapter; you can specify 0 (meaning black), though. See for yourself. A - toggle Adaptive scaling With projection methods None and Mercator, having adaptive scaling on means that, whenever you zoom or specify a window, the coordinates are expanded in such a way that the whole screen will be used. E.g., if you specify a window that is very narrow (in the East-West direction) but tall (in the North-South direction), then with adaptive scaling off you will have most of the screen black; but with adaptive scaling on, the East and West window limits are moved so that the entire screen is filled by the map. This affects future "D" commands only. It has no effect for orthographic and Lambert projection modes. Adaptive scaling is off by default. M - display Status All the relevant settings can be viewed with this command. Use this to determine your current window and projection method, or if you have forgotten what list file you specified, and so on. <blank> - erase prompt Hitting the space bar toggles the prompt display on or off; use this if you want to view a map unperturbed. While drawing, saving or printing, the prompt line is always off. X - eXecute a command file If you perform a sequence of commands often, you may want to automate this task - this is where command files come in. Simply use a text editor to create a file which contains MapView commands and tell MapView to execute these commands by typing "X" at the main prompt and then giving the command file's name. The default extension is .CMD; you may override this default by explixitly stating an extension. As with the "L" command, you may display a directory of command files by answering the file name prompt with "?". The bell signal that ends the processing of list files is inactive while a command file is being executed; nice if you don't want to be disturbed while MapView is churning away. For a different use of command files, see below. - See (iv) below on how to prepare command files. ? - get on-line help A short command line summary will be displayed. In case you're still confused: "If all else fails, read the documentation." (Quotation courtesy of Volker A.Brandt) Q - Quit Well, you've been waiting for that, haven't you. MapView may be run fully automatic - e.g., from a batch file - by supplying the name of a command file on the DOS command line, much as you would via the "X" command (but don't specify the "X" on the command line). Just remember to put a "Q" command in at the end of the command file; otherwise MapView will execute the file given and then wait for you to continue. This feature can also come in handy to override MapView's built-in defaults; if you prefer, say, to start with a clear screen and in orthographic projection mode, create a file (let's make it STARTUP.CMD) that contains the lines e p o 0 0 and start MapView through 'MAPVIEW STARTUP'. (iv) Preparing list and command files ------------------------------------- List files contain the names of map files, one per line. Path specifications may be included, but don't have to, if MapView can find the map files in the current directory or in one specified in the configuration file (see (v) below). In general, no extensions should be given; that way, MapView will use MP3, MP2, MP0, or MP1 map files, whichever it can find; see (vii) below. A special command, 'END', may be used to finish execution of a list file before its physical end. In addition, a colour number may be specified after each file name; if there is one, this colour will override any specified by the "C" command at run-time. (See your system's manuals to find out which number means which colour.) Anything following that number is treated as a comment and is ignored. Lines starting with a ';' are treated as comment lines. Command files contain one command per line, complete with all parameters (separated by blanks), and may contain any command you could give by hand; though it doesn't make much sense to give a "W" command here. If you want to include comments in a command file, the simplest way to do so is to write them on a line of their own that starts with a ';'. And, yes, you may nest command files, but MapView won't keep you from shooting yourself in the foot; so you'd better not try recursion, or nesting too deeply. Both list and command files are text files, as are configuration files (see (v) below). One word on text files - this also applies to command and list files: these files must be plain ASCII and should contain no embedded control sequences or tabs. Most programme editors are capable of producing such files, though not every word processor necessarily does. I'm following a time-honoured practice in advising you to specify non-document mode when using WordStar. (v) The configuration file -------------------------- If you have a hierarchical file structure, you will have to tell MapView where to find its map, list, and command files. Also, a few other parameters that may be set for MapView can be specified here; these things will be used only for special hardware configurations or for particular needs; so, in general, they don't need to be specified at all, and if they do, they won't have to (and, consequently, can't) be changed during execution. To do so, prepare a file MAPVIEW.CNF that contains these data and put it into the current directory. This file should contain one information per line: first a keyword that tells MapView what kind of datum this is, then the value for this parameter, separated by one or more blanks. The first group contains the names of directories to be used. The keywords for this are: LST : where to find list files; CMD : where to find command files; MPX : where to find map files; PIC : where to store picture files. Place the name of the appropriate directory (fully specified) after the keyword, separated by a blank. Note that only one directory may be specified per line; in addition, there may be only one line each of type LST, CMD, and PIC. There may be many MPX lines, though - up to 15, to be exact. The second group is mainly concerned with peculiarities of your graphics equipment and your colouring preferences; the keywords are: MOD : set graphics mode; ASP : correct aspect ratio; GRC : set grid colour; BRC : set border colour; BGC : set background colour. PAL : set one colour in the palette used; PRN : number of printer port; OVP : number of overprintings for hardcopies. This stands in need of some clarification. To start with, your graphics adapter may support various graphics modes: Hercules doesn't, but, e.g., EGA does. MapView always chooses the highest resolution by itself; if you don't like that, you can change it here by including a line starting with 'MOD', then the number of a graphics mode to your liking. Try it out - you can't break anything. - ASP is the only parameter that accepts a real argument; if a full globe comes out distorted on your screen, you can correct this by giving an adjustment factor here which sizes in horizontal direction will be multiplied by. GRC, BRC, and BGC choose colours out of the current colour palette for their respective purposes; this won't help you with monochrome adapters, but otherwise, experiment to find out what you like best. Two special features are involved: a colour of 99 will always be the highest colour available, i.e., in general, white; negative values (for grid and border only) will draw those lines as dotted ones. This is mainly useful on monochrome boards to distinguish grid lines from serious stuff; so that's the default. Otherwise, this feature is not much good on monochrome adapters or screens. - Again, invalid arguments will be ignored. - PAL allows you to change colours in a palette on adapters that support this feature. You'll have to give two integer values on a PAL line: the first is the number of the slot within the palette, the second is the number of the colour. For details, refer to your graphics adapter's or computer's manual. Now for the printer support: usually, MapView uses printer port 1 for hardcopies. If you have connected your printer through a different port, you may specify that number on a PRN line. The range supported is 1 through 4. Finally, OVP allows you to select the number of times the print head moves over each line of graphics output when hardcopying. Overprinting makes the lines look blacker; but, of course, it takes some time. The number may be in the range from 1 to 5; the default is 1, which will suffice in many cases; 2 should definitely be enough. Of course, all this makes only sense for real matrix printers. Again, lines starting with a ';' are treated as comment lines. (vi) Slide and QSlide operation ------------------------------- Once you have created a picture file, you may want to review it later; after all, that's presumably why you made it. For this purpose, Slide and QSlide are provided. They are very simple, non-interactive programmes that read a picture file and display the pictures in it sequentially. At start-up, you may tell them to introduce a delay of so-and-so-many milliseconds between each two pictures, and to repeat the whole sequence so-and-so-often, where 'so-and-so-...' is between 0 and 65535. A repeat count of 0 will repeat indefinitely; a delay time of 0 will give a special maximum delay of some 11 minutes. You may abort operation at any time by pressing any key. There is an additional optional switch, the keypress switch: if you specify "/K" on the command line, pressing a key will not in general quit the programmes but rather immediately switch to the next picture. This is handy for semi-automated slide shows: call Slide (or QSlide) with a delay of, say, 10000 milliseconds (or maybe even choose the extra long delay time as explained above), and hit any key as soon as you are fed up with one particular picture. The keys "Q", "ESC" and "Ctrl-C" may still be used to quit the programme, however. The first time through, Slide will try to read all the pictures into memory and display them from there later on, when you have specified a repeat count greater than 1. If they don't fit, Slide will continue to read pictures from disk repeatedly. If you have a graphics adapter with at least two pages, it will do very smooth swapping. If, or as long as, it has to read from disk, the display rate is about 2 pictures per second; if it takes them from memory, the rate is about 3 per second. (These times are for a 10MHz AT and a 28ms hard disk.) On a 640k PC with no memory hogs installed, about 17 Hercules screens can be held in memory; this figure will be much less for EGA or VGA screens, of course. If you have one of these adapters, you may want to use some form of CGA or Hercules emulation for slide shows. If all the pictures in a file fit into memory at once, you may want to use QSlide instead of Slide. Picture swapping is not so smooth while reading from disk; but once that is done, QSlide will be rocket-fast: you'll get more than 15 screens per second (on a 10MHz AT). This will only work on CGA or Hercules adapters due to size limitations; sorry for this - blame the 80x86 segment structure. - Due to the different screen storage management, there may be slightly less room for pictures; e.g., with 580KB free memory, I can fit 17 Hercules screens into Slide, but only 16 into QSlide. Have a try. There are two example command files for MapView, GRID16.CMD and WORLD16.CMD, which produce files for use with Slide and QSlide; these are designed with the Hercules user in mind. You can take these as a starting point to making your own. Both programmes check if the picture file was produced for the display adapter you are using; if not, they tell you so and quit. Call Slide from the DOS command line via slide <filename> [/R<repeatcount>] [/D<delay>] [/K] or QSlide via qslide <filename> [/R<repeatcount>] [/D<delay>] [/K] (with no blanks except where indicated). The default extension is .PIC. Note that both programmes will not search any paths by themselves; so if you have made up a separate picture directory, be sure to include its name with the file name. (vii) Map files --------------- MapView is made around the world map files provided by Mr John Allison, The World Digitized, Apollo, PA. These files are not part of the MapView package but may be obtained at various bulletin boards and shareware servers. Please, heed his request for a $20 donation. He has also supplied good documentation of the data and discusses strengths and weaknesses. MapView can read three different file formats. The basic format is the MP1 format, as supplied by Mr Allison; these files are plain ASCII. From these files, MP2 and MP3 files are derived, which store latitude, longitude, Mercator equivalent of latitude, and precomputed three-dimensional Cartesian coordinates in binary format; MP2 is mainly for non-80x87 machines, whereas MP3 is designed to take advantage of a math-coprocessor and is also slightly more compact (cf. appendix C below). Both these formats allow for fastest MapView execution but takes up even more space on your disk. Alternatively, you may use MP0 files, which are binary integer values; these are the most compact format, still somewhat faster to process than MP1 files, but by far slower than MP2 and MP3 files. Also, there is a slight decrease in exactness; unless you zoom way down, this should not result in inaccuracies of more than one pixel. There is another advantage to using MP2, MP3 or MP0 files: these include quick-scan information on which region of the Earth they pertain to. What good is this? Well, suppose you have only MP1 files, and suppose further you have displayed a map of the whole world, and now zoom down to some comparatively small region, say Australia. If you forget to switch to an appropriate list file (e.g., AU2), MapView will try to display each of the world map files: no harm done, but you will be kept waiting for a long time while MapView tries to plot all those lines outside of Australia. With MP0, MP2, or MP3 files, however, MapView can quickly determine if a certain map file should be considered for plotting at all, and you'll be done in almost the same time as if you had specified the correct subset of maps. (In fact, this feature practically removes the need for most of the list files, except LEV0 through LEV3 - whichever region you choose to display, just select one of the LEV files according to the amount of information you want.) Of course, you don't have to have more than one format on disk; pick your choice - space or speed. For drawing, if you haven't specified an extension for a file to draw (usually in the list file you are plotting), MapView will try to find a map file with extension .MP2 (in the current directory or any of the subdirectories specified on an MPX line in your configuration file); if you have recompiled MapView to make use of a coprocessor, MapView will look for extension .MP3 instead. If it finds none, it will try a MP0 file, and, as a last resort, a MP1 file. To produce MP2, MP3, or MP0 files from an MP file, you can call Mp1ToMpX from the DOS prompt via MP1TOMPX <filename> [/0 | /2 | /3] where the file name must include its extension MP1. The file must be in the current directory or include a path, and the resulting file is written to the current directory. - Alternatively, if you want to process a group of files, prepare a text file containing the fully qualified file names (no extension) of all the files in the group; the extension must be LST. In fact, you can use such a file later on as a list file; or you can use the list files distributed with this package. Then call Mp1ToMpX from the DOS prompt via MP1TOMPX <listfilename> [/0 | /2 | /3] Again, the file name must include its extension LST, and a path may be specified. /0 will produce MP0 files, /2 will produce MP2 files, etc.; /2 is the default. - Note that MP1TOMPX expects all MP1 files in the current directory, unless specified otherwise. - Hence, to convert to MP2 format the whole bunch of MP1 files as supplied by Mr Allison, group them all together in a single directory; put the file LEV3.LST there, too, and type MP1TOMPX LEV3.LST This process will take about 45 minutes on a 10MHz AT with a 28ms hard disk, time well spent. Producing MP0 files is much faster, of course. - Note that you need not concern yourself with the details of all this if you use INSTMAP.BAT included with the MapView package (see (ii) above). One more note: the binary formats are not very archive-friendly, i.e., they don't compress well under the common compression algorithms, while MP1 files do. If you want to store away full-precision data for later whatever-you-like-to-do-to-data, you'd better use the original MP1 files; they take up much less space (after compression) than MP2 files, and you don't give away precision as you would with MP0 data, which, after compression, are still smaller than the compressed MP1 data. (viii) Trigonometric values file -------------------------------- For fastest MapView execution, you may produce a file that holds precomputed trigonometric values as used by MapView. If MapView finds this file in the current directory at start-up and you have enough free memory, it will read this file and execute faster (at the expense of a slight loss of accuracy - but that should not result in errors of more than one pixel, except at very high magnifications); if it does not find the file, that's fine with MapView, too. In general, the file produced will be called TRIG2.BIN, which is designed for use with MapView as distributed. If, however, you decide to recompile MapView for use with an 80x87, specify "/3" as a command line parameter for TrigCalc. This will produce a file called TRIG3.BIN. - You will notice the speed gain particularly if you use MP0 or MP1 files; see the timings in appendix C below. To make the file, just run TRIGCALC.EXE - that's it. You won't need the EXE file any more, so you may remove it from your hard disk. (Remember to say "TRIGCALC /3" instead if you have recompiled MapView for 80x87 use.) (xi) History ------------ Version 1.0 Original programme by Ton van den Bogert <WWDONIC@HEITUE5.BITNET>, written in TurboPascal 3.01 for Hercules graphics adapter. 2.0 Converted to TurboPascal 5.0 by Gisbert W.Selke <RECK@DBNUAMA1.BITNET>. Removed (hopefully) all Hercules specifics. Now handling orthographic projection properly in all cases. Added Lambert projection. Re-arranged code. Added bells and whistles. Changed command interface slightly. Added support for MP0, MP1 and MP3 file formats. Added configurability. Generalized picture file format. Added compiler switches for easy recompilation on 80x87 systems. Supplied new picture file viewers and file preprocessors. See separate upgrade notice if you have old command files. - Released 12 Jan 1989. (x) Bugs, limitations, future enhancements ------------------------------------------ If a map extends beyond the window specified, the connections between points just barely within the window and their outside neighbours are not displayed. I don't think this is a serious limitation. Support for other types of printers may become available. More projection methods may be added. I haven't tested the colour features, nor have I tested either MapView or Slide on anything but a Hercules graphics adapter. This includes Slide and QSlide. I hope all works as advertised. MapView currently does not allow small areas on the 'back side of the Earth' to be viewed, e.g., from 170° West to 170° East. Some day I'll add this 'wrap-around' feature. MapView will not run on very small systems; it is designed for speed (I/O buffering and the ilk), not for memory size. But then again, who has a 128k machine. Bugs? I'd like to hear about them. Get in touch with me at TapirSoft Gisbert W.Selke <RECK@DBNUAMA1.BITNET> Ermekeilstrasse 28 D-5300 Bonn 1 West Germany Appendix A ---------- This appendix briefly describes the file formats used by MapView. MP0 files These files essentially contain longitude and latitude of map points. Both values have to be multiplied by 0.01 to yield true degrees. In addition, if the resulting latitude is greater than 100, 200 has to be subtracted from it. If so, this indicates that the current point starts a new chain of points; otherwise (i.e., without having to subtract), the current point is connected to the previous point by an approximate straight line (or circle, to be exact). Each record takes up 4 bytes. The first two records are special: instead of belonging to the map data proper, they list the minimum and maximum latitude and longitude present in this file. The Pascal record that describes these data is (where an integer takes up 2 bytes) Type mp0rec = Record ilon, ilat : integer; End; MP1 files These are the original data as supplied by Mr Allison. They contain real type latitude and longitude in plain ASCII format; anything after the second real is junk and should be disregarded. An empty line in the file indicates that the next point is unconnected to the preceding one. Note that the order of latitude and longitude is reversed with respect to MP0 (and MP2) files. MP2 files These files contain pre-processed real data in binary format. These real values are 6-byte reals as required by ordinary (i.e., non-coprocessor) TurboPascal. The first byte is a flag which, when 0, indicates that the current point is connected to the previous one; otherwise, this point starts a new outline. Then come the longitude and the latitude, the Mercator equivalent of the latitude, and the three-dimensional Cartesian x, y, z coordinates of the point, scaled to be on the surface of the standard unity sphere. Each record takes up 37 bytes. The first record in the file is special: its record type is FFh, and it lists the minimum longitude, minimum latitude, maximum longitude, maximum latitude present in this file. The rest of this record is 0. The Pascal record that describes these data is Type mp2rec = Record rectyp : byte; lon, lat : real; merclat : real; xg, yg, zg : real; End; MP3 files This format is nearly identical to the preceding one, except that it uses 4 byte reals (IEEE single precision reals) instead of TurboPascal's 'native' 6 byte reals. See appendix B below on recompilation to make use of this format. - The only things different are: each record takes up 25 bytes, the header record's record type is FEh, and the appropriate Pascal record is Type mp3rec = Record rectyp : byte; lon, lat : single; merclat : single; xg, yg, zg : single; End; Picture files Pictures are stored on disk in a simple, uncompressed way, using variable length records. For each picture, there is a lead-in record of fixed length (12 bytes) that contains information on the file format version, the number of pictures to follow to create a single screenfull (see below), the graphics driver and mode used, the size (in bytes) of the picture being described, and its upper left corner. The next record contains the image as supplied by the TurboPascal 4.0 GetImage procedure, i.e., twice 2 bytes size information, then the actual bit map. Then comes the next picture's lead-in record. - See MAPGRAPH.PAS for a way to write pictures in this format (procedure SAVE), or SLIDE.PAS for a way how to read them. The Pascal record that describes the lead-in record is Type picdesc = Record version, follow : byte; grdriver, grmode : integer; size : word; xmin, ymin : integer; End; To read the image data, take an untyped pointer variable, allocate memory as indicated by the size information, and read the next record into the memory region thus set aside. The value of FOLLOW is usually 0; however, the size of an EGA or VGA screen exceeds the buffer size that can be allocated by TurboPascal. Hence, these pictures are stored in chunks. Each chunk is written to the file like a complete picture, header record and all; each header record's FOLLOW byte gives the number of chunks that will follow the current one, and it is 0 on the last chunk of a screen. XMIN and YMIN specify the region of the screen where each chunk belongs. Configuration, command, and list files These files are plain ASCII files created with any editor capable of not writing special control sequences to the file. Any reasonable editor should be able to do so; however, some word processors may not. (You might just as well cast those into the binary garbage bin, or /DEV/NUL, if you're a Un*x type.) If need be, use the DOS COPY command. Or, horribile dictu, EDLIN. - For particulars, see the sections above explaining what these files should contain, and why. - There remains one file: MAPVIEW.HLP. This file contains the screen (or screens) you get when you type "?" at the main MapView prompt. You can tailor it to your own needs, or translate it into Gaelic, or even German, if you like. Appendix B ---------- A note on recompilation and coprocessor support Since 80x87 math coprocessors are not in general use, MapView, as distributed, is designed to run on non-coprocessor systems. Everything has been set up so that recompilation on an 80x87 machine will automatically produce a MapView version optimized for the additional hardware; there is no need to change the source. Note that the coprocessor version cannot read MP2 files (nor TRIG2.BIN); use the "/3" switch for Mp1ToMpX and TrigCalc to produce the appropriate formats. These latter programmes don't have to be recompiled since they emulate a coprocessor, which is acceptable since they need to be run only once. - If, for some reason, you do not have a coprocessor but want to pretend, you'll have to change the sources of MAPVIEW.PAS, MAPPROJ.PAS, and MAPGRAPH.PAS in one place each: replace the "N-" compiler directives by "N+,E+". Recompilation under TurboPascal 4.0 is also possible; MapView makes no use of new features except the compiler switch "A+", which may be removed without harm. The utility programmes Mp1ToMPX and TrigCalc make use of the compiler switch "E+", too; this can be removed on 80x87 systems only. Otherwise, all references to the variable types SINGLE and EXTENDED have to be removed, too. Appendix C ---------- MapView Timings This appendix shows you what to expect in performance. All the times given have been taken on an AT clone running at 10MHz, equipped with a 28ms hard disk, and no coprocessor. FastOpen had been installed. (These times are one-time measurements, not the results of carefully devised series of experiment.) To plot the outlines of continental Europe, E0, without showing grids, window set to 35°/-10° .. 75°/40°, the times (in seconds) were File format used -- with TRIG2.BIN -- -- without TRIG2.BIN -- Projection type MP0 MP1 MP2 MP0 MP1 MP2 None 11 29 8 11 29 8 Mercator 13 32 8 80 98 9 Azimuthal 19 35 17 56 72 54 Orthographic 38 58 26 123 141 34 Lambert 38 58 34 128 147 62 Using a coprocessor will speed things up considerably, especially if MapView has been recompiled and MP3 files (and TRIG3.BIN) are used; using TurboPascal 5.0 coprocessor emulation will slow operation down, of course. Processing the command file WORLD72, i.e., 72 pictures of the Earth in orthographic projection, viewed from various angles, with coastlines, islands, and lakes (but no political boundaries), and saving all 72 images to disk, took six and a half hours. A complete set of MP2 files had been generated before; otherwise... As for conversion and Slide timings, see the appropriate sections above. Appendix D ---------- General Nonsense and Assorted Rubbish Special thanks go to Ton van den Bogert for the first version of this programme, and to Ken van Camp <kvancamp@ARDEC.ARPA> for the precursor of MP0 files, and his original Swivel programme, which got me started; they both did extensive testing of this release and supplied me with many valuable hints and suggestions for improvements; also to Stefan Kaufmann <UNM407@DBNUAMA1.BITNET> and Rainer Kleinrensing <RAINER @DBNUAMA1.BITNET>, for important hints and beta-testing; Stefan also improved Slide and suggested to me the algorithm used in QSlide. Thanks, of course, to John Allison for all the map data. - Still, all mistakes are my own, as the saying goes; or blame your CPU. Now for the commercial. There is none. At least not from me. I only ask you to give credit where credit is due, and not to give away any of this stuff except as a whole. If you change anything, please, document it, and tell me about your improvements - I'm interested in them, too! The copyright on all this remains with Ton van den Bogert and with me, though; so you're not gonna sell any of this. But, on the other hand: We assume no liability, impress or explied, for this programme's being fit for any particular purpose; the risk is entirely the user's. You have been warned. To my best knowledge, no copyrighted material, except where indicated, is used in this programme; however, nothing should be taken for granted. The following registered trademarks /etc/ have been used: TurboPascal, BGI : Borland International IBM PC, AT : International Business Machines Corporation MS-DOS : MicroSoft Corporation Unix : AT&T Hercules : Hercules Corporation, or whatever they call themselves WordStar : MicroPro International Corporation Epson : Seiko Epson Corporation [ End of MAPVIEW.DOC ]