Tutorial for MAP widget

[andrew at midwestcoastmedia.com]

Klaus-

After further inspection I agree with you that this widget needs a  
proper tutorial. I was looking at the module itself trying to find  
some undocumented features (like a polygon or circle overlay instead  
of just a polyline) and came up empty handed.

After looking at the W3Schools tutorial @  
https://www.w3schools.com/graphics/google_maps_overlays.asp I noticed  
that you could create multiple polyline segments using the native  
Google Maps API. The demo code in the LC 9.0.0 docs (not the  
dictionary, but the doc referenced in my previous post) uses the  
following example:

    put "55,-3,55,-5" into tPolylines["line"]["coordinates"]

It isn't documented, but this is a comma delimited list of lat/long  
value pairs (also separated by a comma) to be used as points for  
connecting line segments. So in the provided example a line segment is  
drawn from "55,-3" to "55,-5" on the map. But you can draw a triangle  
between Edinburgh (55,-3), New York (40,-74), and Cairo (30,31) then  
back to Edinburgh with this:

    put "55,-3,40,-74,30,31,55,-3" into tPolylines["line"]["coordinates"]

The closed triangle needs 4 sets of coordinates, not just 3, so it can  
return to the "home" point. Still not quite the polygon overlay that  
the Google Maps API provides, but a neat option that wasn't evident by  
reading the current documentation.

It's also not explicitly documented that the "color" property will  
accept a RGBA value so the following example provides an orange-ish  
overlay with a ~39% opacity (100 / 255):

    put "228,128,0,100" into tPolylines["line"]["color"]

In fact, the dictionary reference for polylines only shows RGB as an  
example. This is an extremely powerful widget... if you know what it  
is actually doing.

--Andrew Bell


> From: Klaus major-k <klaus at major-k.de>
> To: How to use LiveCode <use-livecode at lists.runrev.com>
> Subject: Tutorial for MAP widget
> Message-ID: <B0A88FFF-4F02-4360-BA45-6CFE085FFCE3 at major-k.de>
> Content-Type: text/plain;	charset=us-ascii
>
> Hi all,
>
> could someone (the mothership?) please create a little tuorial
> for the new MAP widget? This is really not self-explaining.
> How to let the user create a new marker etc...
>
> Thanks a lot!
>
>
> Best
>
> Klaus
> --
> Klaus Major
> http://www.major-k.de
> klaus at major-k.de
>