Shareware Overload Trio 2

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Text File | 1994-09-20 | 33KB | 524 lines

README.MAP 5.9c HOW TO MAKE YOUR OWN MAPS OVERVIEW: My general philosophy is to keep maps simple so that APRS will run quickly on any PC machine, including 8088 laptops, and so that maps can be made by anyone. I had wanted to do APRS for years, but could not get any commercial MAP software company to release map info to the amateur community without royalty and ownership problems. I finally bit-the-bullet and decided to come up with a simple graphical technique that anyone could use and understand. For these reasons, APRS limits the number of points to 1500 and the number of labels to 99; any more detail on one map just clutters the screen and makes it difficult to see all the APRS stations. This does NOT limit overall map resolution, however, since APRS overlays maps of increasing resolution as you zoom in. To see the typical street level ability of APRS, Zoom in to the 1 mile range in the center of Idaho Falls, Idaho. MAP COMMANDS: Before getting into the detail of how to build APRS maps, use some of the MAP-MENU commands in APRS to become familiar with the APRS map structure. You will see how maps are overlayed in a hierarchical manner from the whole world, down to increasing detail. This hierarchical list is established in the MAPLIST.xxx file which tells APRS the names of all the maps available to it, their size, and the location of their center. APRS constantly checks the location of the cursor relative to this list to decide when to load a new map. The following MAP-MENU commands will help you see this hierarchical structure: B - Borders: Shows borders of all MAPS in the MAPLIST.apr file. To see more and more borders, use the F3 key to soom into further detail. If a map border appears, but the map does not come up in APRS, then the MAP file is missing. If the Map file exists but the borders do not show up, then the file is not listed in the MAPLIST.apr file. H - Hierarchy: This is an improvement on the BORDERS command since it colors in the maps in the same sequence as they are listed in the MAPLIST.xxx file. The overlapping colors show the effect of the sequence of this list. If you see any border that is not colored in with its own color, then it will be invisible to APRS, since it is overlapped by other maps of the same area following it in the MAPLIST.xxx file. To correct this problem, move it later in the list than the overlapping map. A - ALTmap: Displays the map UNDER the current map. Since APRS always uses the latest map in the MAPLIST.APR file that meets the current cursor location and screen range, areas where maps overlap may sometime be obscured. This command displays the next higher map in the list. L - Locks the current map. This defeats the normal APRS auto-map select feature so that you will not get a redraw if your cursor gets over on another map during a special event. This also lets you zoom way out to see the actual limits of the data in the map file, even if, for some reason, the map border is different than the actual data. FILES-ChgMapList - This command under the FILES menu, lets you have multiple MAPLIST.xxx files, and to save your favorite one in your CONFIG file. This is a significant improvement so that everyone can keep his local customized MAPLIST.xxx file separate from the generalized MAPLIST.APR distribution file. This also simplifies the task of the state APRS map coordinators. They can now maintain update to date MAPLIST.xx files for their states without ever having to merge them with the normal .APR listings, since they can be swapped out with a single key stroke. METHODS FOR MAKING APRS MAPS There are several methods for making maps depending on the resources available to the user. MANUAL - Ruler and Pencil method. Most APRS maps (60+) were done this way! Just use a pencil and home-made template to determine X,Y offsets from the origin in the upper left corner of the map. Then use a DOS editor to enter the X,Y values into a map file. MAPFIX - This program can edit or modify MAP files. But free-handing of the cursor on the screen is difficult to match real world coordinates. This method is best for sketching in local roads on existing maps. CD ROM - MAPFIX can also inport data points from the 1:2,000,000 USGS CD ROM of the whole USA; but the resolution is only down to the state road level, and 4 to 8 hours of manual filtering is required to eliminate redundant point data. W7KKE has written a conversion for the USGS 1:100,000 CD ROM, but says it takes days of manual effort to put all the data together into a meaningful APRS map, since USGS data is VERY fragmented. AUTOCAD - KG8GE has developed programs for building APRS maps to and from AUTOCAD. See the section at the end of this file. DIGITIZER - MAPFIX can accept input from a digitizer tablet. This makes all points very accurate and is the FASTEST way to inport a map. GPS REPLAY - This is the easiest way to add detail in your area. Just drive around with your GPS, saving APRS track history files. Then use MAPFIX to overlay these histories onto the screen for easy cursor drawing. Look for the sections below that describe each of these methods. The manual method is described first, since it gives you the basic structure of the APRS maps format. GENERAL CAUTION: APRS maps are NOT intended, nor expected to fulfill all map requirements. APRS maps are only intended to provide the user with a visual reference to where things are in a radio network. Once you see where a station is, and you want to see what street he is on, or what address block he is in, you should refer to printed maps of your area or make a higher detail map. Do not waste time trying to put too much detail into APRS maps! Similarly, don't try to label everything. Too many labels makes it hard to see callsigns. Also, while driving along at 60 MPH and 30 second GPS updates, zooming in below about 8 miles makes the map move so rapidly so that fine detail is not needed. I usually stay at the 16 mile scale to see what is comming ahead. This confirms that in most cases a straight line between intersections is just as effective as a very detailed curvy map and only takes 2 points vice 20! So concentrate on plotting the intersections accurrately; if you want to come back later and add more detail curves for artistic sake, that is easy to do with the MAPFIX.bas program. HOW TO MAKE APRS MAP FILES: To see what maps are available to the system, use the MAPS-BORDERS command. This command draws the boundaries of all map files and shows you the areas covered by detail maps. The colors of these borders are proportional to map size. Some of these maps are very detail, and some are just "starter" maps that I have made to give new users in those areas a basic map outline from which to add their own detail. If your local APRS net does not have at least a 64 mile map, please contact me. It is also easy to shift the center and detail of maps to highlight your area. See the section MORE ABOUT MAPS at the end of this file for info on how to center, convert and spawn new maps. Slowly other APRS users are beginning to produce maps. Here are some good map makers and state APRS map coordinators. KA7UUS @ K7BUC.AZ Tuscon AZ KD6MKS Silver Lake CA W7KKE @ KA6EYH#nocal San Francisco CA did Digitizer and GPS code for MAPFIX WA4MEJ Jaxonville FL KD4UYR Clearwater FL N4FOR Savannah GA KG0DW & N0YKX & KI0Q IOWA IA KB5YRZ @ N5SSY#METLA New Orleans LA KD1E @ N8NNN.#SEMI Michigan MI W8VPD Michigan UPPER MI KB8JXO @ W8CQK.#CMH.OH Columbus OH W4NMK Black Mountain NC N2FET New Jersey NJ KD1HA @ KA1RCI.RI Rhode Island RI (new england) WB5DTW SanAntonio TX N3FKV Waco TX N4WJQ @ WA4TFZ.VA Charlottsville VA W8KVK West Va VA W9LZQ Onalaska WI KU0G @ KU0G#NWMO.MO Kansas City MO OVERALL APRS MAP FILE FORMAT: In any map file, the first 8 lines define the origin and scale. Comment text is permitted on these first 8 lines after the initial data value and a comma. See the example map below for Colorado. The remainder of the file just lists X,Y points that form the map features such as roads and rivers. To end each such feature and begin another, APRS uses a 0,0 entry. The next feature begins with the value of the line color, followed by the feature name. At the end of this file, is a 0,-1 which marks the end of points data, and the beginning of the list of map labels. See the COLORADO map example below and the section on map labels. MANUAL DOS TEXT EDITOR METHOD: Simply use a DOS editor to make a list of points for APRS to use in drawing line segments. Note that the coordinates are listed as X,Y where X is horizontal and Y is vertical. This is backwards from the usual order that we list LAT (vert) and LONG (Horizontal), so be sure to put the horizontal (X) value first. You can use any editor to prepare a map file. Simply use a chart that has lat/long references and select an origin beyond the upper left hand corner of the area you want to cover. That point is 0,0 and all points are measured from there. (negative numbers are OK if you later add points behind the origin, but the - is an extra character that slows down file loading); similarly, an X value of 0 is not permitted since it is used to indicate separations between the end of one feature and start of another. MAP SCALE: Next choose an appropriate scale in pixels-per-degree of longitude and latitude for the area you want. Since EGA graphics has a 350/640 pixel resolution, I have found that 120 pixels per degree (2 pixels per minute) is excellent for large state maps. I used 12 pixels per degree for the whole US. By keeping the scale number an integer multiple of 60, you avoid any future roundoff and truncation errors due to ZOOM functions and when converting points from one map scale to another. I have used 6,12,24,30,60,120,300,600, 1200, etc. It takes 1200 pix or more in order to resolve city streets. If you use too fine of a scale then you are limited as to how far the map can extend. Points with values greater that 999 should be minimized and no values should be bigger than about 1100 or there is a chance APRS will crash on very zoomed-in maps. The further you zoom in, the larger the values become until you get an overflow error. MAP RANGE: Since APRS handles range scales as integer powers of 2, I suggest making most maps slightly larger than any given power of 2. This is so that you can place the cursor in the center of the map, and pretty much see all of it at once. If you make the size of your map just under a power of 2, then you can never see the whole map at that range. Going down a scale permits you to see all of the map, but only a smaller portion of it at a time. To make it easy to hit the center of a map with the cursor, I usually make my maps with a range scale about 10% larger than an even power of 2. MAPLIST.apr: This file contains the list of all map files available to the APRS program and decides which map is loaded for every location of the cursor. The first 3 lines of the file also contain the default LAT/LONG and Range for the first map loaded. The program uses the default LAT/LON to center the first map each time the program starts up (on unregistered users). The normal distribution copy of MAPLIST.APR contains the default coordinates for the center of the US. These values are ignored when a saved backup file is loaded using the FILES-LOAD command, or when a registered user has saved his default location in his CONFIG file. So to force APRS to start up at your location, you can either 1) change the default location in the MAPLIST file, 2) move the cursor to your location and use FILES-SAVE to save a backup file with you at the center, or 3) if you are a registered user, save a config file. The MAPLIST.APR default location is also stored in the #1 MAP HOT KEY so that you can instantly zoom out to the default map (the USA) with a single key stroke. This is useful for doing a quick glance at HF mobiles that might be comming in through a GATEway! ADDING MAPS: To add a map to your system, look at the MAPLIST.apr file. It contains a list of all maps useable by the system. There can be multiple MAPLIST.xxx files. The MAPLIST.APR file comes with the APRS distribution and contains all regional, and state maps, plus some representative local maps. You can either add your map to this file, or add it to any local state lists that might be available. Currently there are complete MAPLIST.xxx map files for many states such as Calif and Ohio. The MAPLIST.OH file lists over 40 local Ohio maps! To add your map, simply add a line that contains the MAPname, LAT, LONG, MAPrange, and comments. The LAT/LONG are in decimal degrees and describe roughly the center of your map. The MAPrange tells the system to load this map if the cursor ever falls within this range of the center. Actually it is a little more complicated. The given map will not be used until the cursor location plus the current range scale in all directions fully falls within the boundaries. HINT - so that your detail map seems to blend in with the next larger map, add enough rough features and points to your borders to surround your fine detail area with crude detail out to MAX Range beyond. Then when the screen centers on a point near the edge of your fine detail, your map doesn't just stop but includes crude detail to all edges. Currently APRS can only use 140 maps in MAPLIST.apr. To make room for new maps, but keep old ones handy for later use, You can place a (*) at the beginning of a line to tell APRS to skip that map. Also you can add some comment lines at the designated space in the file (beginning with *) so that you can leave notes as to what that particular MAPLIST file represents. There is also a comment field for each map. If you have no comments, you MUST place a comma at the end of the line. MAP HIERARCHY: It is important to place maps in decending order. The last map in the list that contains the given cursor position will be used. If a larger map covering the same area as a smaller map follows it later in the list, then the larger map will always be found last and will be used, instead of the desired smaller map. You can see the this effect, by using the MAPS- HIERARCHY command. If maps overlap in your area, use the MAP-ALT command to temporarily see the map beneath the present map. You can also use the MAPS-OVERLAY command to overlay the larger map onto the present map. Using this feature, you could make two maps of the same area and scale. On one you could put rivers and roads, on the other you could put counties, property lines, and grids. Then by listing the gridded map first in the MAPLIST.apr file, it would always be superceeded by the road map, but could be summoned up by hitting the MAPS-OVERLAY command! MAP FEATURES: APRS displays all map features by drawing lines from point-to- point. Each feature begins with 0,0 followed by the line color and a name for the feature, followed by pairs of x,y points using the scale you chose. The feature name is not used, but is useful for identification during editing. In APRS, there is no limit on the number of features, But the total number of points must remain below 1500. Since the MAPFIX.BAS program does, however, display these feature names during on-line editing, there is a limit of 99 in the array used to hold these names temporarily. The POINT values are positive to the right and down. The end of a feature is simply the 0,0 which starts a new one. After the last feature, there is a special 0,-1 which indicates the end of all feature information and the beginning of the labels list. MAP COLORS: APRS recognizes certain map colors for turning on and off certain map features. For this reason it is a good idea to use my standard colors. I made most map features using the brighter colors since they are easier to see on a color monitor outdoors. In recent versions, you can change the background color with the Tint command or dim all colors using the MAPS-FEATURES-DIM command. Map colors are automatically dimmed when you ask for a MAPS-BORDERS display so that the map edges show up brightly. Here are my standards. The * indicates that the color is uniquely recognized by APRS for special handling such as the FEATURES command: 0 - Black (normal background) * 8 - dark gray (Railroads) 1 - dim blue 9 - Bright Blue 2 - dim green *10 - Bright Green (Interstates) *3 - dim cyan (Rivers) *11 - Bright Cyan (Major rivers, Coasts) 4 - deep red (state roads) *12 - Bright Red (major roads) 5 - dim violet 13 - Bright Violet(special routes/events) *6 - dim orange (state/county lines 14 - Bright Yellow (Cities,airports) *7 - gray (back roads) 15 - Bright White (Labels and CALLS) MAP LABELS: Labels are drawn on maps at given lat/long coordinates. The labels are listed at the end of each map (up to 99). Each label has a range scale associated with it, so that not all labels are visible at all range scales. As you zoom in to finer and finer detail, you can make more labels appear. The first line in the labels list has a leading 0 and then any any comments. From then on to the end of the file, each line consists of 4 fields separated by commas. First is the label text (up to 12 characters long) followed by the LAT, LONG and RANGE. LAT and LONG must be given in decimal degrees. The MAPFIX.bas program displays the location of the cursor in decimal degrees for this purpose. Labels are plotted right justified. This means they will be plotted to the left of the given point. A way to visualize how a label will appear is to assume the label has a following period (.) and that the period is the location where the label will be plotted. Labels are right justified so that they do not overprint station callsigns which are all left justified. Since absolute LAT/LONG reference is used, labels can be transferred with out any change to any scale map. You may decide to change the range size so that the label shows up sooner or later on different maps. Please note, however, that labels are printed on the normal EGA screen 24 line raster, so they can be off their exact location by almost a full text line vertically, and one full character horizontally. Take this into account when placing labels. You can also build APRS symbols directly into MAPS! Instead of a text label, simply make the first three characters of the label be a $ followed by the symbol character, followed by a hexidecimal number from 1 to F that indicates the desired color for the symbol. The remaining 8 characters can be used for a conventional label at the same location. For example, look at the VORTAC's (aircraft nav aids) that I added to the ALASKA maps. They are listed in the map file as $VEANC,lat,long,rng. The V is the VORTAC symbol, the E is hexidecimal for 14 or the color yellow, and ANC is the label for the ANChorage VORTAC as it will appear on the map. EXAMPLE: The following map file constitutes a trivial state map of Colorado. The first 8 lines are the fixed format lines which define the origin and scale. Next are the features for the state borders and for Denver. Finally are the map labels. To see how this map looks, move the cursor to the center of Colorado on the US map and page-down to the 256 mile scale. 41.0, latitude origin (equates to 0,0 in) [Notice how comments can be on] 110.0, long of origin (coordinate system) [the ends of these first lines] 60, pixels per deg of lat/long [and 1st line of each new line] 39,LAT of map center (For ur reference only. Value in MAPLIST.apr is what) 105.5,LON of map center (is actually used as the center and Range for maps ) 200,MapRange 4,minimum range (APRS does not use this, it now computes min range) * This single comment line can contain anything... more or less 0,0 6,Colorado state line 59,0 59,240 479,240 479,0 59,0 0,0 14,Denver city limits 300,68 289,77 300,85 311,77 300,68 0,-1 (0,-1 indicates end of map features) 0,Comments or notes... etc ( note that the 0, is required ) Colorado,40,105,200 Denver,39,104,100 NOTE: The 7th line showing a min range used to be important. Starting with a full scale map, each time you page-down (zoom in) you are doubling the value of each pixel lat/long value. If any of these numbers ever exceed the maximum permissible value of 2 byte integer math (32,000) then the program will crash. To prevent this, APRS assumes that there will not be any data points larger than about 1100 and will not draw your map to a scale that would multiply this number too big. This is why APRS will not draw the USA map smaller than about 32 miles. MAPFIX.BAS: This QBasic program may be used to make, test and edit your maps. It helps you to quickly display single maps and to use the cursor to identify individual map point coordinates. It also has a readout of the cursor in decimal degrees which is required for locating labels and map Centers. It can be used to add, move and delete map points and save a new file. It can overlay a GPS track history file over the map you are drawing so you can make your roads as accurate as GPS! It has a DIGITIZER INTERFACE SO YOU CAN DIRECTLY DIGITIZE ANY MAP! It can also GENERATE A 64 MILE APRS MAP DIRECTLY FROM THE USGS 2,000,000:1 CD ROM. BUT IT STILL TAKES 4+ hours to manually reduce the number of redundant points from the CD from over 5 MBytes down to a 15K APRS size! MAPCNVRT.BAS: This QBasic progarm may be used to convert any one map to a different LAT/LONG origin or different Pixels-per-degree resolution. Use it with the QBasic editor for piecing together features from one map to cut and paste into another map. Say you are building a fine detail map, but want to use the statelines and interstates from a larger map. Just use the editor to remove all unnecessary points from the big map, keeping all the features that you want to retain and move to your new map. Then save it with a TEMPORARY name and then run it through MAPCNVRT.BAS to re-compute all of the map points. Then use this new file as the beginning of your new map. You can also use the point-add-delete function in MAPFIX.bas to fine tune these points. TECHNIQUE: See the sketch above (not available in text file) which shows how simple it is. Most maps have LAT/LONG lines around the borders. If you are using 240 pixels per degree for a state size map, then each LAT/LONG line corresponds to a multiple of 240. Simply mark on the borders of your original map these values 240, 480, 720, etc. Then make a smaller template which matches the size of one square of LAT/LONG lines. Draw a finer grid of lines every 10 pixels on the template. Then to locate the coordinates of any point on the map, simply orient the template with a major LAT/LONG square, and interpolate the point within the grid on the template which represents a 10x10 pixel area. For transfering features from one map scale or origin to another, Use the QBasic program called MAPCNVRT.BAS which will re-compute all point values. Then use a text editor to re-do the LAT/LONG and range and to cut and paste the necessary map labels on the end. CAUTION: since many highway maps are Lambert Conformal instead of Mercator projections, use the center square in your map for making the template to minimize errors. Further, be careful of highway maps that only have tick marks along the borders for LAT/LONG. If the map is not a Mercator projection, then you cannot just draw a straight line from left to right connecting latitude marks. Longitude lines are straight on a Lambert Conformal, but not latitude lines! SPECIAL EVENTS: Conversly, absolute accurracy is only important if there will ever be a GPS or LORAN station involved in your net. A map with little relationship to true LAT/LONG is perfectly useable in some APRS applications as long as all stations in the net are using the same map and no one is using GPS. So feel free to draw quick simple maps for special events even as small as a few square blocks without worrying about exact LAT/LONG. Objects on one station screen will still be in the same location on all other screens! Use the Chess board example at 25N 90W to play chess on the air! But GPS is comming, be prepared! (PACCOM TNC's now come with a GPS interface built-in!) MORE ABOUT MAPS PART 2 With the advent of low cost GPS, most mapmakers are now beginning to add LAT/LONG to most new maps. Our 7-11 convenience store maps now even include map booklets which have a LAT/LONG grid on every page! The grid lines are 5 minutes apart which is exactly 10 pixels if you use 120 pixels per degree as I did for some larger APRS state maps. This means that each grid square is a 10x10 pixel area from which map coordinates can be typed directly into a text editor without any drafting aids! Simply compute the grid coordinates of the corner of each page in the book based on your overall map origin and start entering points! NOTES ABOUT STARTER MAPS: Some of the larger starter maps that I provided use a scale of 120 pixels per degree and have an origin that is suitable for about a 400 mile square area. This area usually covers from one to several states and is good for area maps. With the whole map visible, one pixel represents abt .25 mile resolution. The first step in customizing maps to your area is to take the starter map and start adding roads and features in your area. Since all maps in the APRS system are limited to a maximum of 1000 data points, however, these large area starter maps can usually contain only the interstate roads, the state lines, and major rivers and 4-lane highways. This is perfect for most VHF applications. But as more and more people add detail closer to home, smaller maps need to be "spawned" off to make room for more detail. The following sections describe how to spawn maps and convert points from one map to another. MAP CENTERING: Most of you do not live in the middle of a starter map and so your detail will be off center. To make a more pleasant transition as you zoom into your area using APRS, you may want to simply change the center and range of the starter map to be centered on your area with a range suitable to the amount of detail you have added. To do this, simply edit the line for your starter map in the MAPLIST.apr file to your desired center and range. Keep the original starter map for others to use by adding a (*) to cause APRS to skip it when loading the MAPLIST.apr file. As the number of points in your map grows, you may need to throw out some of the points which are beyond your area of interest. Use MAPFIX.bas to delete points. See the next section on map spawning. O | O | O | ---------------------- ------------------------ -------------------- | | | | ---------- | | | | MAP A | * | | | MAP C | | | | | | | | ----------- | | | | | --------| | | MAP B | | | | | | | * | | | |*| | | | * | | | | | --|------- | | X| | | | | | | | | ---------- | | | ----------- | | | | | | | | | | | | | -------------------- ---------------------- -----------|------ | | MAP D | NEW CENTER & RANGE MAP SPAWNING MAP --------- CONVERSION MAP SPAWNING: In the figure above, map A is the original starter map with the origin at O. Using 120 pixels-per-degree resolution, all points within a square area 8 degrees on a side (about 400 miles) can be resolved with pairs of 3 digit numbers. As the number of points in such a regional area map fills up towards the 1500 limit, it is necessary to start new smaller area maps such as B, C, and D above to permit finer detail to be added. Spawning a new map is easy. Simply use a text editor to create a new mapfile and copy all of the features out of the original map that fit within the new map area. Then save this new map and add its name to the MAPLIST.apr file giving a center and range appropriate to the new smaller area covered. Now add new roads and features in the area of interest. Notice that since the same origin and 120 pixel-per- degree scale are still used among all maps spawned from the same starter map, features and points can be moved among those maps by simply cut-and-paste. MAP CONVERSION: When it is desired to move features and points from one map to another map which has a different origin (X) or resolution, then use the MAPCNVRT.BAS program. First spawn a new map which contains all of the points that are to be moved. Then run the MAPCNVRT program giving the new origin and resolution. The resulting MAPTEMP.MAP file contains a copy of those features and points ready to be cut-and-pasted into the new map (D) with the new origin (X) and resolution. This process is useful when creating finer detail maps of an existing area and you want to transfer the interstates and larger map features down to the finer detail map without having to re-do the data points. You can use MAPFIX.bas to add new points to a road when building a finer detail map, or to delete points when building a larger map where extra fine detail points are not needed. PIXELS-PER-DEGREE: Although my early regional maps used 120 pixels per degree, most of the newer maps generated from my CD rom use at least 450 to 600 pixels- per degree. This gives finer detail resolution on the smaller 64 mile maps. You can use 1200 ppd to resolve down to large city blocks, but to get them accurately, you should consider 2400 ppd which can resolve down to about 100 feet. Notice that as you increase the number of pixels-per-degree, you also reduce the maximum size that a map can cover. This keeps the numbers from getting too large and causing an overflow condition. A 1200 ppd map should be used for map areas less than 50 miles and so forth. AUTOCAD MAPS! Jim Krist KG8GE has done a marvelous job of writing programs to use AUTOCAD to make APRS maps. He has done every street in the town of MARION Ohio. HIs program is named PLT2MAP and permits you to use a CAD plotter to make AUTOCAD maps and then convert them to APRS. Registered copies of his software can be obtained for $25 from him at 315 Hane Ave, Marion, Ohi0, 43302. I am not familiar with AUTOCAD, so if AUTOCAD is your bag, you might be interested in his software. Remember, however, that if you have a digitizer tablet, you can draw APRS maps directly with the APRS MAPFIX.bas program.