The Point of it All
I use this map to plan bike rides around Phoenix. It shows me where the bike lanes
go and I click off a route so I can see the distance and make sure I don't get
in over my head. If you want to use it for finding bike routes in Phoenix,
you can probably get right to it. If you want to get fancy and use other maps,
you'll want to read these instructions.
Track points
When you begin tracking a route on the map, it will put dots everywhere you click
and lines connecting the dots.
Clicking the shaded
!
button will cycle through available marker colors. All dots and lines will be
drawn in whatever color you select. This button is also used to return to
point drawing after using the Remove Point and Insert Point buttons.
The Õ button will remove the last track point
from the map. Note that it removes the point from the end of the route, not
necessarily the point added most recently.
The " button will remove any point. To use it,
click it then click track points that you want to remove. To stop removing points
you can click the same button again, or click the
! button.
Alternatively, you can just begin clicking new locations on the map.
The y button will insert a new point in the
route. The new point will appear where you click, and the route will be adjusted
to include the new point. To stop inserting points click the
! button.
To erase all of the old track points and begin a new route, click the
M button. This will clear all track points and
reset the distance to 0 units. It will not erase the current scale of the map.
Maps
The page will load with a bike map of Phoenix by default. If you want a different map,
specify its URL when you request the page like this:
mapdistance.html?map=http://www.srpnet.com/water/canals/graphics/CanalMap.gif
or off your own machine like this:
mapdistance.html?map=file://c:/maps/hikingmap.jpg
If you use the default map you do not need to specify a scale, but other maps can't
calculate distances until you set a scale. You'll know you need to do this if you see
a distance of "Infinity.0." I realize that this behavior could be construed as a bug,
but I sort of enjoy the idea of "Infinity to one decimal place," so it stays.
I got this map from the
MAG
web site, and I think it was awfully nice of them to publish the
front and
back sides in the first
place.
Scale & Precision
To set the scale of a map, you will need to know the distance between two points on it.
To do this:
Enter the number of units between your two points into the text box, then press
the "Set" button. Click one point, then the other. The page will calculate the distance
between the points and calibrate itself. If, for example, the map you are using has a
scale printed on it that displays a distance of 5 miles, you would enter "5" in the text
box, click the "Set" button, then click the beginning and end of the scale. All distances
would be in miles.
Alternatively, you can enter the the number of units and the number of pixels
in the URL, like this:
mapdistance.html?map=http://www.srpnet.com/water/canals/graphics/CanalMap.gif&units=30&scale=168.
This link says "It takes 168 pixels to make 30 units (miles) on this map."
Because maps vary in size, resolution, and accuracy, it is probably silly to worry about
highly precise decimal numbers. You can use the
ç and
è buttons to see less or more
decimal places.
Moving the control panel
If the control panel is obscuring an important part of the map, you can use the
ë
button to move the control panel to the opposite corner of the screen.
Saving a route
My current hosting arrangements don't allow much latitude in terms of server-side
scripting or database connectivity. Nevertheless, I thought it would be nice to be
able to save routes. If you want to do that, click the "Map to XML" button at the
bottom of the browser window & keep the text that shows up in the text box (you'll
have to save it to your own computer or email it to yourself or something). Later,
when you want to reload the route, enter that text in the text box and click the
"XML to Map" button. That will plot the route on the map and display the distance.
This saves the route along with the map and the scale (so you don't have to go clickin'
the scale off next time).
You can also use it to save just a map & scale (without any route points).
For example, if you paste this into the text box:
<route map="img/bikemap150.jpg">
<scaleBegin x="1054" scrollX="1101" y="719" scrollY="0"/>
<scaleEnd x="48" scrollX="0" y="719" scrollY="0"/>
<units>25</units>
</route>
and click "XML to Map" it will load a ridiculously large map of Phoenix with the scale
already set for you.
Note that this is equivalent to specifying the link
mapdistance.html?map=img/bikemap150.jpg&units=25&scale=2107
which also contains the map, scale, and units.
Requirements
I'd be pretty surprised if you were even reading this on a browser other than IE because
that's the only one I wrote it to work on.
You'll need the MSXML parser from
Microsoft too.
Standard Disclaimer
This little script is provided as-is with no warranties and confers no rights.
This product is not intended to diagnose, treat, prevent, or cure any disease.
If itching or rash develops, discontinue use.
Copyright © 2005, Andy Allen. Please see the
license agreement for full licensing details.
Me
You can reach me at .
If you find this tool useful, I'd like to hear from you.
