feat(cesium): support altitude modes via ground primitives

[wallw-teal]

This addresses lines/polygons either drawn by the user or from data sources. In addition, getCoordinateFromPixel was improved with Cesium's recommendation for handling the terrain vs. ellipsoid cases.

Tests:
General Features

• Test drawing box/circle/polygon in 2D, 3D (no terrain), and 3D (terrain), and all in multiple projections.
• Test loading lines/polys from a file and changing the altitude mode
• Test the case from Places have interesting altitudes #381

Places

• Verify that adding a new place allows you to choose an Altitude Mode and that the preview feature is correctly updated on each change
• Verify that editing the place populates the Altitude Mode dropdown correctly
• Verify that reloading the application displays the geometry correctly
• Verify that exporting the place results in the appropriate <altitudeMode> tag being added to the KML
• Verify that importing that KML results in the correct altitude mode
• Add a line and polygon with altitude to places and repeat the above steps

Feature Requests:

• Can places be assigned an altitude if terrain is on in 3D when created via Layers widget (pasting coordinates or clicking on the map)?
• Can non-point places support terrain like polygons? Currently they are flattened.

Discussions:

• Cesium upgrade and new items like Scene.highDynamicRange
• Interpolation granularity

[wallw-teal]

Note that this does not address Measure Lines. The calculation for those is following the surface of the ellipsoid, and therefore that is where they will be drawn.

We certainly have the capability to do that calculation over terrain should anyone request it.

[schmidtk]

• Creating buffers (on point/line/polygon) throws a lot of errors and doesn't create the buffer.
• Polygon/line drawing gets clipped by the globe.

[justin-bits]

1. Places have a negative altitude when created from the context menu with terrain off in 3D
   

2. Can places be assigned an altitude if terrain is on in 3D when created via Layers widget (pasting coordinates or clicking on the map)?

3. Console error thrown on attempting to draw box, 3D. Map locks up (won’t pan).
   

4. Line for polygon disappears depending on orientation
   

[schmidtk]

@justin-bits

Console error thrown on attempting two draw box, 3D. Map locks up (won’t pan).

Did you do a yarn upgrade? Cesium was updated in this PR, and it looks like you're on the previous version. That would cause the error you mentioned.

[justin-bits]

Altitude update (1) after Will's fix:

Altitude is non zero with terrain off after mode change. On 3d terrain off>2d>3d save place it shows altitude on saving the place (slightly positive to slightly negative). Not 100% consistent. 4.65 meters comes up frequently.

[justin-bits]

Doing yarn upgrade, will update.

[justin-bits]

1. Still valid (initially negative altitude, now 4.65)
2. Outstanding question/request.
3. Resolved by yarn upgrade.
4. Still valid (line clipping).
5. (new) The globe looks terrible, already mentioned by Kevin.

[wallw-teal]

1. I'm concerned that Cesium might have a bug there. Both the forums and the docs indicate that the value returned by Camera.prototype.pickEllipsoid() should have a height of zero.
2. Sure, but I'm going to avoid adding more features until the current bugs are cleared.
3. w00t
4. This is due to our interpolation granularity defaulting to 100,000m while Cesium's internal granularity (which we have turned off) defaults to 9,999m. If you change the value in Settings > Interpolation from 100km to 10km that fixes it. However, that's 10x the number of vertices per area.

[justin-bits]

6. Console errors thrown on buffering a box/circle/polygon/line and place (3d, terrain on/off). Probably same thing Kevin mentioned.

Uncaught TypeError: Cannot read property 'x' of undefined
    at v.setBatchedAttribute (Cesium.js:471)
    at Y (Cesium.js:471)
    at H.update (Cesium.js:472)
    at M.update (Cesium.js:474)
    at a.update (Cesium.js:483)
    at a.update (Cesium.js:483)
    at a.update (Cesium.js:483)
    at at (Cesium.js:522)
    at it (Cesium.js:522)
    at $e (Cesium.js:522)

7. Can non-point places support terrain like polygons? Currently they are flattened.

[wallw-teal]

That is the same thing that Kevin mentioned. It has to do with polygon fills and I'm looking into it.

[wallw-teal]

For the interpolation granularity (affecting clipping through the earth), we could simply enable Cesium's interpolation in addition to ours. In the event that ours is at the default 100km or greater, the polygon on our side will keep the same number of vertices and only the Cesium primitive will have more at their default of 9.999km. This does appear to be a little chunky (slow) in my tests though (largely because drawn items are rendered with async: false and are updated quickly).

Edit: I'm gonna push this and see how it looks for you

[wallw-teal]

Just don't forget to put Settings > Interpolation > Granularity back to 100km.

[justin-bits]

• Console error on buffering resolved
• Save places altitude working correctly
• Still getting clipping for lines/polygons, though it appears to be significantly better

Stale.

[wallw-teal]

Setting these items appears to fix the globe rendering issues.

scene.highDynamicRange = false;
scene.globe.showGroundAtmosphere = false;

Most of it is solved by the second one, so we may want to leave highDynamicRange on.

[wallw-teal]

I think this is ready to go other than deciding whether or not scene.highDynamicRange should be on or off.

[schmidtk]

• The create/edit place controls don't seem to update the feature/label consistently. Using Relative to Ground, changing the altitude updates both the feature/label. With Absolute, changing the altitude only updates the feature. Turning on Clamp to Ground updates the label but not the feature.
• When terrain is enabled, Relative to Ground positions the label correctly but the feature still uses absolute positioning.
• Changing Altitude Mode for lines/polygons doesn't update the preview feature. It does update the feature when you finish editing.
• Altitude Mode on lines/polygons isn't saved correctly on application refresh. It seems to use absolute positioning on the feature, but editing the place always populates Clamp to Ground.
• My personal preference would be disabling highDynamicRange. Visually I think it's too dark/muted and reduces contrast between tiles/features, making it harder to distinguish what you're looking at.

[wallw-teal]

I think all of those issues are fixed. I'll note that Cesium does not actually support relativeToGround for lines or polygons. It is picking either GroundPrimitive (clampToGround) or Primitive for polygons, and GroundPolylinePrimitive/Geometry or Primitive/PolylineGeometry for lines. There was no option similar to heightReference for BillBoards. absolute and relativeToGround are displayed the same in those cases.

See CesiumGS/cesium#6976

[justin-bits]

@wallw-bits

1. Error on creating places (with defaults) under the projections 3031 and 3413. These places shift around the globe on changing projections. On removal via the layers dialog, they also remain on the map.

2. Box/circle/polygons shift around on the map when changing projections. Even when returning to the projection in which they were created, they are in dramatically different positions at different sizes.

3. Units on Altitude field do not respect user settings, it defaults to meters. Also, precision is unreasonably high.

4. On opening the Add Place dialog, the place is not visible. It only becomes visible on clicking OK.

[wallw-teal]

1. That is unrelated to this ticket
2. I'm not able to reproduce that
3. That is unrelated to this ticket
4. I'll fix that