# OverviewMap not showing layers

**URL:** <https://community.thinkgeo.com/t/overviewmap-not-showing-layers/5775>\
**Category:** WebForms\
**Created:** [April 5, 2011, 9:13am UTC](https://community.thinkgeo.com/t/overviewmap-not-showing-layers/5775 "2011-04-05T09:13:13Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![David10](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/d/c4cdca/32.png) [@David10](https://community.thinkgeo.com/u/David10)\
**Post date:** [April 5, 2011, 9:13am UTC](https://community.thinkgeo.com/t/overviewmap-not-showing-layers/5775/1 "2011-04-05T09:13:13Z")

</div>

Hello,

I&nbsp;am&nbsp;able&nbsp;to&nbsp;set&nbsp;thinkgeo&nbsp;minimap&nbsp;to&nbsp;work,&nbsp;yet,&nbsp;i&nbsp;have&nbsp;the&nbsp;need&nbsp;to&nbsp;costumize&nbsp;the&nbsp;control&nbsp;to&nbsp;create&nbsp;a&nbsp;separate&nbsp;logic&nbsp;from&nbsp;the&nbsp;main&nbsp;map.&nbsp;I'm&nbsp;having&nbsp;some&nbsp;trouble&nbsp;doing&nbsp;this:&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;this.OverviewMap&nbsp;=&nbsp;this.Map.get\_MapEngine().getControl('OverviewMap');

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(this.OverviewMap&nbsp;!=&nbsp;null)&nbsp;{  
  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(this.Map&nbsp;!=&nbsp;null)  
  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;var&nbsp;mapParser&nbsp;=&nbsp;this.Map.\_MapParser;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;var&nbsp;layers&nbsp;=&nbsp;new&nbsp;Array();

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;(var&nbsp;i&nbsp;=&nbsp;0,&nbsp;layerIndex&nbsp;=&nbsp;0;&nbsp;i&nbsp;\<&nbsp;this.Layers.length;&nbsp;i++)&nbsp;{  
  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;layers.push(mapParser.getLayerByJson(this.Layers_));_  
  
_&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}_

&nbsp;this.OverviewMap.layers&nbsp;=&nbsp;layers;

this.OverviewMap.update();

&nbsp;}

&nbsp;The&nbsp;final&nbsp;result&nbsp;is&nbsp;a&nbsp;gray&nbsp;miniMap&nbsp;with&nbsp;no&nbsp;layers.&nbsp;What&nbsp;i'm&nbsp;i&nbsp;doing&nbsp;wrong?&nbsp;I've&nbsp;tried&nbsp;diferent&nbsp;aproaches.&nbsp;I've&nbsp;tried&nbsp;building&nbsp;the&nbsp;overviewMap&nbsp;myself&nbsp;and&nbsp;adding&nbsp;it&nbsp;to&nbsp;map&nbsp;controls&nbsp;collection&nbsp;like&nbsp;this:&nbsp;

var&nbsp;controlOptions&nbsp;=&nbsp;{  
  
&nbsp;maximized:&nbsp;true,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  
  
&nbsp;layers:&nbsp;layers  
  
};

this.OverviewMap&nbsp;=&nbsp;new&nbsp;OpenLayers.Control.OverviewMap(controlOptions);  
  
&nbsp;&nbsp;  
  
this.Map.get\_MapEngine().addControl(this.OverviewMap);

&nbsp;

&nbsp;

In&nbsp;this&nbsp;case,&nbsp;how&nbsp;do&nbsp;i&nbsp;get&nbsp;map&nbsp;options&nbsp;without&nbsp;having&nbsp;to&nbsp;write&nbsp;it&nbsp;one&nbsp;by&nbsp;one?

&nbsp;

&nbsp;

&nbsp;

&nbsp;

---

<div class="post-metadata">

**Author:** ![ThinkGeo](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/thinkgeo/32/25029_2.png) [@ThinkGeo](https://community.thinkgeo.com/u/ThinkGeo)\
**Post date:** [April 6, 2011, 5:10am UTC](https://community.thinkgeo.com/t/overviewmap-not-showing-layers/5775/2 "2011-04-06T05:10:26Z")

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Hi&nbsp;David,&nbsp;  
&nbsp;&nbsp;  
&nbsp;Welcome&nbsp;to&nbsp;ThinkGeo&nbsp;support&nbsp;forum.&nbsp;  
&nbsp;&nbsp;  
&nbsp;We’re&nbsp;working&nbsp;on&nbsp;your&nbsp;issue,&nbsp;will&nbsp;let&nbsp;you&nbsp;know&nbsp;if&nbsp;we&nbsp;have&nbsp;any&nbsp;progress.&nbsp;Please&nbsp;keep&nbsp;an&nbsp;eye&nbsp;on&nbsp;this&nbsp;thread.&nbsp;  
&nbsp;&nbsp;  
&nbsp;Regards,&nbsp;  
&nbsp;&nbsp;  
&nbsp;Ivan

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<div class="post-metadata">

**Author:** ![David10](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/d/c4cdca/32.png) [@David10](https://community.thinkgeo.com/u/David10)\
**Post date:** [April 6, 2011, 9:23am UTC](https://community.thinkgeo.com/t/overviewmap-not-showing-layers/5775/3 "2011-04-06T09:23:34Z")

</div>

Thank&nbsp;you,&nbsp;&nbsp;  
&nbsp;&nbsp;  
&nbsp;Looking&nbsp;forward&nbsp;to&nbsp;hear&nbsp;from&nbsp;you.

---

<div class="post-metadata">

**Author:** ![ThinkGeo](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/thinkgeo/32/25029_2.png) [@ThinkGeo](https://community.thinkgeo.com/u/ThinkGeo)\
**Post date:** [April 7, 2011, 8:46am UTC](https://community.thinkgeo.com/t/overviewmap-not-showing-layers/5775/4 "2011-04-07T08:46:43Z")

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Hi&nbsp;David,

For&nbsp;your&nbsp;reference,&nbsp;here&nbsp;are&nbsp;answers&nbsp;for&nbsp;your&nbsp;questions:

**1.&nbsp;The&nbsp;final&nbsp;result&nbsp;is&nbsp;a&nbsp;gray&nbsp;miniMap&nbsp;with&nbsp;no&nbsp;layers.&nbsp;What&nbsp;i'm&nbsp;i&nbsp;doing&nbsp;wrong?**

In&nbsp;OpenLayers.Control.OverviewMap.,&nbsp;the&nbsp;source&nbsp;code&nbsp;of&nbsp;method&nbsp;"update"&nbsp;is&nbsp;below:

`update: function() {	if(this.ovmap == null) { this.createMap();	} if(this.autoPan || !this.isSuitableOverview()) { this.updateOverview();	} // update extent rectangle	this.updateRectToMap();}`

So&nbsp;if&nbsp;we&nbsp;need&nbsp;to&nbsp;customize&nbsp;the&nbsp;OverviewMap,&nbsp;we&nbsp;may&nbsp;need&nbsp;to&nbsp;set&nbsp;null&nbsp;to&nbsp;ovmap&nbsp;first.

`this.OverviewMap.ovmap = null;this.OverviewMap.layers = layers;this.OverviewMap.update();`

**2.&nbsp;In&nbsp;this&nbsp;case,&nbsp;how&nbsp;do&nbsp;i&nbsp;get&nbsp;map&nbsp;options&nbsp;without&nbsp;having&nbsp;to&nbsp;write&nbsp;it&nbsp;one&nbsp;by&nbsp;one?**

The&nbsp;mapOptions&nbsp;is&nbsp;in&nbsp;the&nbsp;format&nbsp;of&nbsp;JSON.&nbsp;It's&nbsp;a&nbsp;property&nbsp;in&nbsp;OpenLayers.Control.OverviewMap.&nbsp;I'm&nbsp;not&nbsp;sure&nbsp;what&nbsp;do&nbsp;you&nbsp;mean&nbsp;by&nbsp;saying&nbsp;"get&nbsp;map&nbsp;options&nbsp;without&nbsp;write&nbsp;it&nbsp;one&nbsp;by&nbsp;one",&nbsp;do&nbsp;you&nbsp;mind&nbsp;provide&nbsp;us&nbsp;detailed&nbsp;description?

Regards,

Ivan