\
**Category:** Rails\
**Created:** [November 23, 2006, 8:18am UTC](https://www.ruby-forum.com/t/google-map-to-html-not-working/76995 "2006-11-23T08:18:20Z")\
**Posts on this page:** 6\
**Page:** 1
**Author:**  [@jacquie](https://www.ruby-forum.com/u/jacquie)\
**Post date:** [November 23, 2006, 8:18am UTC](https://www.ruby-forum.com/t/google-map-to-html-not-working/76995/1 "2006-11-23T08:18:20Z")
Hi,there
This question might sound a bit out-dated but I am still struggling with
it.
When I try to display the google map in my application, I rendered
@map.to\_html like everyone else does, but didnt get any result. The
error shows as follows
ActionView::TemplateError (You have a nil object when you didn’t expect
it!
The error occured while evaluating nil.zoom=) on line #1 of
app/views/admin/content/\_place\_map.rhtml:
1: \<% @map.zoom = 4 %\>
2: \<%= @map.to\_html %\>
By using the google map API,I followed the instruction in readme
strictly. register for a new key and include the cartographer module in
RAILS\_ROOT/config/environment.rb by require ‘cartographer’
It looks like I was able to get @map.to\_html in my controller but not
able to render in the view.
Anyone encountered this problem before?
Thanks for any help!
---
**Author:**  [@jacquie](https://www.ruby-forum.com/u/jacquie)\
**Post date:** [November 23, 2006, 11:05am UTC](https://www.ruby-forum.com/t/google-map-to-html-not-working/76995/2 "2006-11-23T11:05:23Z")
Jacquie,
It looks like your view can’t see the @map instance, any chance you are
actually trying to make this call in a partial or that the object
wasn’t created correctly in the contoller? Can you paste a code snippet
for us to look at?
---
**Author:**  [@jacquie](https://www.ruby-forum.com/u/jacquie)\
**Post date:** [November 23, 2006, 11:28pm UTC](https://www.ruby-forum.com/t/google-map-to-html-not-working/76995/3 "2006-11-23T23:28:21Z")
Thanks for your reply,glenn.
Yeah,thats what I thought,but not sure why.
I have @map in my map\_controller.rb as is shown below
def index
# create the map
@map = Map.new(:name =\> ‘placemapper’, :width=\>800, :height =\> 600,
:controls =\> [:zoom, :type], :draggable =\> true)
# default type
@map.type = :map
# default zoom level
@map.zoom = 13
```
places = Hash.new
place = Place.find(:first, :conditions => [%{location = ? },
```
params[:query].downcase])
if !place.nil?
longitude = place.longitude
latitude = place.latitude
longlat = [longitude, latitude]
```
places[longlat] = [place.address << "," << place.suburb << "," <<
```
place.state \<\< “,” \<\< “Australia”]
```
i = 0
places.each { |key,value|
text = ""
value.each { |v| text << v }
@map.markers << Cartographer::Marker.new( :name =>
```
“marker\_#{i}”, :position =\> key, :info\_window =\> text )
i += 1
}
# center the map
@map.center = places.keys.last #@map.center and @places.keys.last
both are arrays
redirect\_to :controller=\>‘admin/content’, :action
=\>“display\_map.rjs”
else
redirect\_to :controller =\> ‘admin/content’, :action
=\>“get\_more\_info.rjs”
end
end
Then in views/admin/content/display\_map.rjs
page.insert\_html :bottom, ‘my\_map’, :partial =\> ‘place\_map’
page.visual\_effect :appear, ‘my\_map’
Then in views/admin/content/place\_map.rhtml
\<% @map.zoom = 4 %\>
\<%= @map.to\_html %\>
would it be because I used rjs? but the second redirect\_to works fine.
anybody has some ideas?
Thanks a lot!
---
**Author:**  [@jacquie](https://www.ruby-forum.com/u/jacquie)\
**Post date:** [November 24, 2006, 3:17am UTC](https://www.ruby-forum.com/t/google-map-to-html-not-working/76995/4 "2006-11-24T03:17:43Z")
Thanks, Scott. I solved this problem by rendering an action under the
same controller.
Thank you all!
Scott B. wrote:
> On 11/23/06, jacquie [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:
>
> > ```
> > @map = Map.new(:name => 'placemapper', :width=>800, :height => 600,
> > longitude = place.longitude
> > @map.markers << Cartographer::Marker.new( :name =>
> >
> > ```
---
**Author:**  [@jacquie](https://www.ruby-forum.com/u/jacquie)\
**Post date:** [November 24, 2006, 1:58am UTC](https://www.ruby-forum.com/t/google-map-to-html-not-working/76995/5 "2006-11-24T01:58:25Z")
On 11/23/06, jacquie [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:
> ```
> @map = Map.new(:name => 'placemapper', :width=>800, :height => 600,
> longitude = place.longitude
> @map.markers << Cartographer::Marker.new( :name =>
>
> ```
>
> =\>“get\_more\_info.rjs”
> \<% @map.zoom = 4 %\>
> \<%= @map.to\_html %\>
>
> would it be because I used rjs? but the second redirect\_to works fine.
>
> anybody has some ideas?
It’s because you are doing a redirect. That is causing to to jump to a
new
page and start a brand new request, which no longer has all of the code
you
ran before the redirect in memory. You need to a do a render instead of
a
redirect.
–
Scott B.
Electro Interactive, Inc.
Office: 813-333-5508
> **[Electro Interactive - Web Development. Ruby on Rails. Web Standards.](http://www.electrointeractive.com)**
>
> Electro Interactive is a full service new media design and development company.
---
**Author:**  [@jacquie](https://www.ruby-forum.com/u/jacquie)\
**Post date:** [November 27, 2006, 12:53am UTC](https://www.ruby-forum.com/t/google-map-to-html-not-working/76995/6 "2006-11-27T00:53:22Z")
Unfortunately I need to keep on this topic since the map is not
displaying at all.
in my controller, i set up a breakpoint before rendering the rjs
template.
@map.center = places.keys.last
breakpoint
render :action =\>‘index.rjs’
I print out the @map.to\_html at this breakpoint and it gives out
It looks fine.
However,in my webpage,I’ve only had
The webpage where it should display the map is completely blank.
anyone has the same/similar problem before?
Thanks!