flsamap1.zip - APRSdos maps of Sarasota County, FL. 3/23/97 Commissioned by Ron Wetjen, WD4AHZ, wd4ahz@gte.net README.txt -- Documentation for the local area APRS map maintainer. See also, INTRO.txt, a short introduction to using these maps. APRSdos detailed street maps from US Census TIGER/Line 1995 files. Generated by Alan Crosswell, N2YGK, n2ygk@weca.org, using tig2aprs. If you would like maps like these for another county, please contact me for more info. The zip files ------------- The distribution is in a bunch of zip files meant to be unzipped relative to the APRS main directory. flsamap#.zip - Sarasota County, FL APRSdos maps flsawin1.zip - WinAPRS map # is 1 or 2 (the files are split up to fit on floppies). flsawin1 is a map to use with WinAPRS/MacAPRS and is not needed for APRSdos. The zips are in 1.44MB chunks so they can fit on a 3.5" floppy. Within each zip file are the following subdirectories: maps - contains the map files maplists - contains the maplist files tig2aprs - miscellaneous junk that you can unzip and look at but not necessary for use with APRSdos. To get setup on APRSdos, CD to the APRS directory and UNZIP each of the files. For example, for Sarasota: cd \aprs unzip a:flsamap1.zip maps/* maplists/* More details about the contents of the subdirectories follows: MAPS - APRSdos map files ------------------------- Maps rendered at ranges of 16,8,4,1 miles plus one big APRSdos map. Naming scheme is: flsah000.map - 32 mile map radius (one map) flsa4###.map - 16 mile map radius (one map) flsa1###.map - 1 mile map radius (hundreds of maps) ### is a 3-digit automatically generated (meaningless:-) map number MAPLISTS - Maplist files ------------------------ maplist.sa? - a set of maplists for Sarasota County Where ? is one of blank,A,1,2,3,4 maplist.xx - All maps with no overlaps. This gives you full coverage but you have to HOME at the crosshair to see each map. Panning (tracking, etc.) off the crosshair will cause APRSdos to back off to the next larger (less detailed) size. maplist.xx? - Where ? is one of 1,2,3,4 for the NW,NE,SE,SW quadrants. Full coverage (maps plus 3 overlays for each). This maintains the same level of detail when panning across maps zoomed in at 1/2 the map scale. For example, at the 1/2 mile scale, you can pan relatively smoothly across the screen as APRSdos automatically loads the next map that fully encloses the viewing area. Due to maplist size limits, all detail maps cannot fit in a single county-wide mapllist. Each maplist starts with what was in MAPLIST.FL2 which is a Florida statewide maplist found in: ftp://ftp.tapr.org/tapr/SIG/aprssig/files/maps/PCMaps/flmaps02.zip You also may want to acquire the following maps if you don't already have them: ftp://ftp.tapr.org/tapr/SIG/aprssig/files/dosstuff/APRSdos/semaps12.zip ftp://ftp.tapr.org/tapr/SIG/aprssig/files/dosstuff/APRSdos/emaps13.zip TIG2APRS - Other files ---------------------- The following files are in the tig2aprs directory: log.??# Execution log from tig2aprs showing what it did. ?? = county, # = range (h,g,8,4,1,w) flsawin.zip Contains a single large DOS-format map, flsaw000.map, which can be used with WinAPRS or MacAPRS. This map can have as many as 100,000 data points. maplist.xxa The reference list of all APRSdos maps supplied. Use as a source of mapnames when customizing your own maplists. Maplist details --------------- Each maplist file line is commented with details that will help you manipulate the maps. Except for the root map, each maplist entry is either a quadrant of a parent map which was tiled because it had too many datapoints, or an overlap of a base map. You can toss all the overlaps for example and still have full coverage; just not smooth panning. Comment examples: ..., NW quadrant of flsa8000 ..., E overlap of flsa1018 The map referenced for quadrants doesn't actually exist, since it was split into 4, but you can see more about it in the log file. Map details ----------- Maps have been generated at several levels of detail, which for lack of a better term, are designated by the map range in miles for which they seemed to fit. The levels are: >16 - Major features only such as interstate highways, oceans, large rivers. 8 - Adds major highways. 4 - Adds minor highways. 1 - Full street detail Since APRSdos limits a given map file to 3000 data points, it is impractical to have a reasonable looking map with full detail at any greater than a 1 mile range. In certain dense urban areas the best one gets is a .5 mile map range. You will see some of these near the center of Yonkers. If you actually read a map file in a text editor, you will see a few items worth noting: In the comment block you'll see something like this: Map generated by tig2aprs from 1994 US Census TIGER/Line. tig2aprs (c) 1996,1997 Alan Crosswell N2YGK map has 2965 points f=20 wf=0.107 sf=0.165 The third line shows the number of data points, how badly "fuzzed" the map was (how far apart two data points can be and still be considered the same. f=20 is the worst I will settle for); what percent size a water body had to be to not be filtered out of the map (small lakes that cover less than 10.7% of the map area were tossed); and a factor that I can't explain to myself even that shows how close the slopes of two line segments have to be in order to be collapsed into one (saving a data point). Each map feature is commented with details as well. For example: 3 ,(H11)Gottfried Creek 16365788 This is an APRS color "3" (blue; see README\MAPMAKIN.TXT) feature. The Census Feature Class Code is H11 (perennial stream or river), "Gottfried Creek" is the name (according to the Census records) and the 16365788 is the unique TIGER/Line ID (TLID) of the feature (or one of the features when they get chained together). Note that similar features that are end-to-end are glued together to save data points, so the TLID is only for one end of the chain. There are probably 20 or more TLIDs associated with the feature. There are also a bunch of labels at the end of some map files which correspond to names of places that come from the TIGER/Line data. Appropriate APRS special symbols are included. You will frequently find 2 or 3 words stacked one above the other. This is because APRSdos is restricted to a 12 character label, so longer multi-word names get split up by tig2aprs. $}2Bay Plz at,27.115775,82.433934,2.0 Bird Bay,27.114982,82.433934,2.0 Village,27.114189,82.433934,2.0 The labels come from the US Census concepts of places, key geographic locations, and point and area landmarks. More info --------- Source code and documentation for the free program that generates these maps is available at http://www.cloud9.net/~alan/ham/aprs. Information about the US Census TIGER/Line data can be found at http://tiger.census.gov.