MAPS100K.txt                   FINAL NOTES ON BUILDING 100K MAPS

    In just the last month, the MKMAPHK.exe program written by KE4XF,
Jack Cavenaugh, has made it possible for anyone with the $32 USGS CD 
ROM for their area to make street level maps.  See my MAPS-CD.txt file 
and the details in MKMAPHK.txt.  Bill Knolle, KE4EER was the first to 
produce prodigous numbers of maps and developed the technique for just 
gridding the desired city into slightly overlapping 1 mile maps (2 mile 
center-to-center).  The result is a predictable number of contiguous 
maps that give street level detail anywhere in the city.  But this IS 
ONLY THE BEGINNING TO MAKING A USEFUL MAP SYSTEM.  

     The problem is that the 1 mile maps are not even viewable unless
you zoom to the 1 mile range and happen to hit the exact center of the 
map.  You have a better chance of getting a map to come up at the .5
mile scale, but only if you are still reasonably near the center of
one of these maps.  If you are on the border between any two maps, you
will NEVER see the maps, because APRS cannot find in the maplist, a map
which can completely contain your screen.  This is very frustrating to
users to have the detail more or less done, but to not be able to access
it in a seamless maner.  This file describes what I do next to build a
seamless map system.  There are sort of two approaches, but a mix of 
the two is probably the best.

BRUTE FORCE:  This method takes the existing grid of adjacent 1 mile maps
and creates a completely new grid of 1 mile maps whose centers are at
the CORNERS of the original grid of maps.  The process uses MAPFIX and
the alt-IMPORT command to import streets from adjacent maps into each of
these new maps.  This covers the corners of the original grid, but you
still have no overlap at the top and bottom centers of the original
grids.  This requires yet another grid offset by 1/2 mile up and down.
(There is plenty of left/right overlap built into the original maps
due to the horizontal aspect ratio used by MKMAPHK.)  This process will
result in trippling the original number of maps...

JOINING SMALLER MAPS:  This method looks for adjacent maps that are
relatively small (7 to 15K) that can be combined with others and still 
stay below the 30 k limit.  Because MKMAPHK makes maps of the same 
aspect ratio as the PC screen, the optimum joining of maps to give a 
larger map with the same aspect ratio is to combine four in a quad.  
Around the edges of your area, you can also combine maps vertically
and horizontally.  Then move the center and range of this combined
map further outside of the area so that the white box does border
the combined maps perfectly.  I have combined as many as 4 horizontal
1 mile maps into a big 4 mile map centered 2 miles north of town.
Similarly I make a 4 mile map to the south and east and west.  Although
most of these map areas are blank, the 4 combined 1 mile maps do show
up now at the 4 mile range when your cursor is "north" of town.  This
always works around the edge of your city or town, because all of the
maps generated in these areas have significantly fewer points. 

In the center of a city or town, this will rarely work because of the
density of detail.  But you may be able to still join at least two
adjacent maps.  ALthough the resulting 2 mile map will have lots of blank
space at the edges, this central map may be listed first in
the MAPLIST, so that other laps will cover those areas when the user
ZOOMS.  Whenever you use a map with large blank areas, always be sure
that the maps that fill in those areas are listed LATER in the maplist.

OVERLAING INTO A BIGGERMAP:  MKMAPHK can make 4 and 8 mile maps, but
it automatically leaves out most of the finer detail.  If your 4 or 8
mile map has room, use the ctrl-OVERLAY feature in MAPFIX to
temporarily overlay each of the 1 mile maps to look for any gray level
main thoroughfares that need to be drawn into the bigger maps.  Look
for winding roads or long straight ones that locals will recognize.
Use the alt-NEW and alt-ADD commands to rapidly draw in these streets.
Do not worry about getting EVERY point, just a good approximation of
these thoroughfares, since this larger map will only be visible at the
larger scale.  The exact detail will appear as the user zooms in.
Only a few of these thoroughfares are needed to give the user the 
visual structure of sub-divisions and known landmarks.

     All of these methods use either the IMPORT or the OVERLAY feature
of MAPFIX.  Actually these two commands are really the same routine.
The IMPORT brings points INTO the current map under construction, 
whereas the OVERLAY only draws them on the existing screen so you can 
SEE the points temporarily.  This is so you can add more features to
your working map by drawing over selected features in the OVERLAYED
map (without having to IMPORT them ALL).  Once you have given the file 
name for either command, you can re-use the same map over and over again
with a single keystroke.  This is particularly valuable with the Overlay 
command.  To control the points that you want to IMPORT, the WHITE box 
representing the map CENTER and RANGE is a very powerful tool.  The 
IMPORT function will ONLY import points that will fit INSIDE the white 
BOX where ever it is.  You may move the box edges around anywhere you 
want with the alt-CENTER and alt-RANGE command.

     When building a combined map by IMPORTING adjacent horizontal maps, 
there will usually be significant horizontal overlap.  To avoid the waste 
of this duplication here is the process I use.

1) Load the first map
2) ^OVERLAY the next map to see where it is going to fall
3) Use alt-C and alt-R to move the white box so that one of its edges
   makes a clean line just inside the existing map edge
4) Now hit alt-IMPORT and the second map comes in just up to the white
   line with minimal overlap.  Now there will only be a few streets that
   duplicate and they can be removed using the FIND and DELETE commands.
   

SUMMARY:  Once you have finished generating your original 100k map grid,
and can see the general density of the streets throughout the city or
town, you can use the above techniques to build your maps into a seamless
system of maps that in most cases is transparent to the user.  This 
probably takes as long or longer than the original MKMAPHK process, but
it is ESSENTIAL for user satisfaction.  As an example, I took the 12 maps
generated by KE4EER for Hattiesburg and was able to combine them into
only 4 maps.  A northern and southern 4 mile map, and two middle east 
and middle west 2 mile maps.  This combined with the major street
thoroughfares that I overlayed into his original 8 mile map makes a 
pretty good seamless map system.  
