Sun shadow in ArcGIS Online should include terrain

1463
9
02-13-2020 12:36 AM
Status: Open
MarianneLindau_Langhelle
New Contributor II

The dynamic widget for daylight and shadows in webscenes is awesome. But because our landscapes in Norway are anything but flat, we usually can't completely trust the result because it only shows shadows cast from vector data, i.e. multipatch buildings. Usually the shadows cast by terrain is equally important. My idea is that you develop this function further to include the shadows cast by the elevation surface/ DTM raster.

I have used an inelegant workaround up until now by draping av a fishnet vector layer over the terrain. But the result is pixellated and does not look great.  

9 Comments
DirkSilbermann

Yes, same here: we miss sun shadows from terrain in deep valleys, too, both in Arcgis Online Webscenes and  Arcgis-Pro!

Pål_Herman_Sund

Hi @MarianneLindau_Langhelle @DirkSilbermann and the others kudoing this Idea. It has been a while but I just remembered while discussing with a college yesterday. Seems to be sort of terrain shadow implemented in ArcGIS Online now.

Pl_Herman_Sund_0-1677680123041.pngPl_Herman_Sund_1-1677680153469.png

Probably old news for most of you.

DirkSilbermann

Thanks for the hint @Pål_Herman_Sund !

Well - Terrain is now better shaded respecting the Daylight settings, but still does not cast (hard) shadows like Buildings. Only the surface is darker shaded depending on slope and sun position.

This valley remains in direct sunlight, altough the shadow of the hill should be visible on the lower Building and opposite hillside.  
The two Buildings on top of the hill cast their lonely shadows to the opposite hillside, but without the shadow of the terrain it looks awkward...    and the Building in the valley still seems to be in the sun which fools solar analysis.  

DirkSilbermann_0-1677681839592.png

Esri ist on the right way, but not there, yet ...

Pål_Herman_Sund

@DirkSilbermann agreed! I happened to test further after my comment and noticed the same behavior as you are pointing at. The comment from my college was he had seen "something new" with respect to sun/shadow/terrain in the latest JavaScript api. Not there yet - agreed again. Cheers Pål Herman/pH

SveinungBertnesRåheim

Tromsø kommune has added a 3d-model based on 10m elevation grid. Added that as a layer to the 3d-model. Then when you model shadows, you also model shadows from the terrain. Work fine, I think.

I have not checked the format of the 10m elevation grid.

https://arcg.is/nCn5e

SveinungBertnesRåheim

@Pål_Herman_Sund @DirkSilbermann 

 

From Tromsø kommune, I understand that they convert a 10 m grid DEM-raster to a 10 m "fishnet" multipatch-dataset. At least, that what I have done. And it works! But it consumed quiet a few credits to publish a scene layer with appr. 2 mill features.

I made the hosted scene-layer white and set it to 99% transparency. Buildings shadows will no longer go through small hills etc:

Without terrain as multippatch, building shadows goes through a hill:SveinungBertnesRheim_0-1682506488108.png

With terrain as multipatch, the hill casts its own shadow, no false building shadows.SveinungBertnesRheim_1-1682506488156.png

You can watch the result live in our 3d-client for Bodø. Only visible from Skau to Saltstraumen.

Technically I did this. I am open for improvements.

  1. Downloaded DEM10 from høydedata.no
  2. Converted DEM to polygon (Raster calculator to convert rastervalues to integer).
  3. Interpolate shape with "Vertices only" activated. Get elevation from DEM10 to each vertice in the polygon layer
  4. Layer to 3d Feature class
  5. Splitted the multipatch featureclass into to separate layers to be able to publish to AGO
  6. Published as hosted Scene service
  7. Set Transparancy to 99%
Support1

Hi @SveinungBertnesRåheim "terrain" as a multipatch is the workaround which has been valid for quite a few years. As you state, it does potentially consume "some" credits. I think we all (correct @MarianneLindau_Langhelle @DirkSilbermann ?) would like terrain shadows to be more similar to the result of multipatch objects

Improvements in your workflow? I guess what you outline is just fine and similar (but more detailed) to the description given in the idea by Marianne.

best
pH 

Pål_Herman_Sund

Sorry I did post my comment with the wrong user account 😄 The joy of multiple ArcGIS Online accounts

Pål Herman / pH

DirkSilbermann

Thanks to share your Workarround to force TerrainShadows using transparent multipatch fishnet, which can be usefull for small projects or corse Terrain I guess. 

But still a workaround with downsides, its correct that we would like to see the Terrain/Elevation Layers to cast shadows similar to multipatch...