# Displaying heatmaps as contours

**URL:** <https://discourse.slicer.org/t/displaying-heatmaps-as-contours/8314>\
**Category:** Support\
**Created:** [September 5, 2019, 6:33pm UTC](https://discourse.slicer.org/t/displaying-heatmaps-as-contours/8314 "2019-09-05T18:33:59Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![ahmedhosny](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ahmedhosny/32/2272_2.png) [@ahmedhosny](https://discourse.slicer.org/u/ahmedhosny)\
**Post date:** [September 5, 2019, 6:33pm UTC](https://discourse.slicer.org/t/displaying-heatmaps-as-contours/8314/1 "2019-09-05T18:33:59Z")

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Hello -

I have 3 layers visualized in slicer as follows:  
**L:** a label map  
**F:** a heatmap of continousos values (think of it like an RT dosemap, but I am not using the SlicerRT extension)  
**B:** an image

Currently, the heatmap is on top of the image. I would like to view the two simultaneously. For now, simply reducing the opacity of the heatmap works. Ideally, viewing the heatmap as contours would provide the best viewing experience. Any ideas on how to do that within Slicer?

The heatmap is treated as an image not a label map when loading. If “label map” is checked, and the toggle showing “label map volume with regions outlined” is on, you get a pixelated view, which is expected since the values are continuous not discrete as in a common label map.

Thanks so much.

Here is a screenshot.

 ![Screenshot](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/a/6/a6b5bb64ba4a9e802486b2b8094e520605ae6492.jpeg)

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [September 5, 2019, 6:37pm UTC](https://discourse.slicer.org/t/displaying-heatmaps-as-contours/8314/2 "2019-09-05T18:37:37Z")

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This feature is implemented in SlicerRT extension’s [Isodose module](https://www.slicer.org/wiki/Documentation/Nightly/Modules/Isodose). It can visualize iso-surfaces as surfaces in 3D and as contours in slices. You can use any volume as “dose volume”.

[![](https://www.slicer.org/w/images/thumb/8/89/SlicerRT0.6_Isodose.png/1080px-SlicerRT0.6_Isodose.png) ](https://www.slicer.org/w/images/thumb/8/89/SlicerRT0.6_Isodose.png/1080px-SlicerRT0.6_Isodose.png)

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<div class="post-metadata">

**Author:** ![ahmedhosny](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ahmedhosny/32/2272_2.png) [@ahmedhosny](https://discourse.slicer.org/u/ahmedhosny)\
**Post date:** [September 6, 2019, 2:33pm UTC](https://discourse.slicer.org/t/displaying-heatmaps-as-contours/8314/3 "2019-09-06T14:33:53Z")

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Thank you @lassoan! It throws “Selected volume is not a dose”, but it seems to be a warning only.

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<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [September 6, 2019, 2:45pm UTC](https://discourse.slicer.org/t/displaying-heatmaps-as-contours/8314/4 "2019-09-06T14:45:52Z")

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Yes, it should work well. To avoid the warning, set `DicomRtImport.DoseVolume` attribute of the volume to `1`.

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**Author:** ![cpinter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cpinter/32/7995_2.png) [@cpinter](https://discourse.slicer.org/u/cpinter)\
**Post date:** [September 6, 2019, 3:59pm UTC](https://discourse.slicer.org/t/displaying-heatmaps-as-contours/8314/5 "2019-09-06T15:59:37Z")

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Yes it’s only a warning.

To convert the volume to dose using the UI, you can right-click your volume in the Data module (make sure it’s under a study that’s under a patient), and choose Convert to dose volume.