When I try to use GPolyLine.fromEncoded, I get an error:
"Error: a has no properties
Source File: http://www.google.com/mapfiles/78/maps2.api/main.js
Line: 50"

The error seems to be persistent, even in a very simple example, see:
http://blog.ozo.dk/gmap/gmap2.html

Any help is very much appreciated!!

That's completely the wrong syntax for GPolyline.fromEncoded.

It's not your fault, the documentation in the class reference page is
wrong.

The syntax is like this
http://www.google.com/apis/maps/documentation/#Encoded_Polylines

not like this
http://www.google.com/apis/maps/documentation/reference.html#GPolyline

--
The Blackpool Community Church Javascript Team
http://www.econym.demon.co.uk/googlemaps/

On Jun 2, 5:29 pm, ConnorZ <kristiankj...@gmail.com> wrote:

Your syntax for the call to GPolyline.fromEncoded is
incorrect.  Try

map.addOverlay(
  new GPolyline.fromEncoded({
    color: "#0000ff",
    weight: 4,
    opacity: 0.8,
    points: "_eunI_wfhA_ibE_ibE",
    levels: "BB",
    zoomFactor: 32,
    numLevels: 4
  })
);

I've written some stuff on encoded polylines that
you might find helpful:
http://facstaff.unca.edu/mcmcclur/GoogleMaps/EncodePolyline/

Mark

Thanks guys! You are the best!! I had really struggled with this for
quite some time! You don't expect the API documentation to be wrong!!

Well - now it works... To start with I set numLevels to 18 and use
"PPPP..." as my points. I know this can be optimized, because not all
points are needed at all zoom levels. But for now it is sufficient
that the line shows up at all!

But another thing: Can you explain me what "zoomFactor" is used for??
The API documentation says:
"For optimization, the zoomFactor parameter should reflect the
approximate magnification between the different zoom level groups
specified in numLevels. For example, given a doubling for each zoom
level and about 4 zoom levels in each group, this value should be set
to 16."

I don't understand the "example". How is 16 calculated?! How can the
parameter be used in general?

Regards
Kristian

On Jun 3, 2:39 am, mark mcclure <mcmccl...@unca.edu> wrote:

On Jun 3, 4:47 am, ConnorZ <kristiankj...@gmail.com> wrote:

As I understand it zoomFactor should indicate the
ratio of magnification factors between one level
of the polyline and the next.  Each level of the
polyline corresponds to a group of levels of the
map and the magnification factor doubles for each
increment.  Thus, if one level of the polyline is
supposed to correspond to four levels of the map,
the zoomFactor between levels of the polyline
would be 2^4 = 16. In my experience, you can
frequently fiddle with this parameter quite a bit
without major changes in the line.

Frequently numLevels and zoomFactor should satisfy
zoomFactor^numLevels = 2^18, when working with a
G_NORMAL_MAP.  This could change if you are
working on a map with a different number of zoom
levels itself.  It is also possible that the
structure of the line might dictate a different
zoomFactor.

Hope that helps,
Mark