IAE: "POLYGON cannot have zero area" after adding custom MVT source

[selimachour@…]

What steps will reproduce the problem?

1. add my mvt source ​https://tiles.where.tn/mvt/{z}/{x}/{y}.pbf (contains data about Tunisia only)
2. Zoom in

What is the expected result?

What happens instead?

JOSM Exception

Please provide any additional information below. Attach a screenshot if possible.

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2021-06-02 22:03:39 +0200 (Wed, 02 Jun 2021)
Build-Date:2021-06-02 20:11:30
Revision:17919
Relative:URL: ^/trunk

Identification: JOSM/1.5 (17919 en) Linux Mint 19.3 Tricia
Memory Usage: 1163 MB / 2540 MB (626 MB allocated, but free)
Java version: 1.8.0_292-8u292-b10-0ubuntu1~18.04-b10, Private Build, OpenJDK 64-Bit Server VM
Look and Feel: javax.swing.plaf.nimbus.NimbusLookAndFeel
Screen: :0.0 1366×768 (scaling 1.00×1.00)
Maximum Screen Size: 1366×768
Best cursor sizes: 16×16→16×16, 32×32→32×32
Environment variable LANG: en_US.UTF-8
System property file.encoding: UTF-8
System property sun.jnu.encoding: UTF-8
Locale info: en_US
Numbers with default locale: 1234567890 -> 1234567890
Desktop environment: X-Cinnamon
Java package: openjdk-8-jre:amd64-8u292-b10-0ubuntu1~18.04
libcommons-compress-java: libcommons-compress-java:all-1.18-1~18.04
libcommons-logging-java: libcommons-logging-java:all-1.2-2
fonts-noto: fonts-noto:all-20171026-2

Plugins:
+ CADTools (1008)
+ ColorPlugin (1537115529)
+ DirectDownload (35640)
+ DirectUpload (35640)
+ EasyPresets (1612708244)
+ HouseNumberTaggingTool (35640)
+ PolygonCutOut (v0.7)
+ apache-commons (35524)
+ apache-http (35589)
+ continuosDownload (91)
+ editgpx (35562)
+ jaxb (35543)
+ jna (35662)
+ jogl (1.2.3)
+ log4j (35458)
+ mapwithai (1.8.2)
+ markseen (14)
+ measurement (35640)
+ reltoolbox (35640)
+ reverter (35732)
+ terracer (35640)
+ utilsplugin2 (35691)

Tagging presets:
+ https://github.com/kendzi/Simple3dBuildingsPreset/releases/download/0.9_2018-05-08/s3db-preset.zip

Map paint styles:
- https://josm.openstreetmap.de/josmfile?page=Styles/AddressValidator&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Admin_Boundaries&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/DigiRoadBusStops&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PublicTransport&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PublicTransportV2&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/RU-SubwayEntranceLabeling&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Noname&zip=1
- https://github.com/osmlab/applepaintstyles/archive/master.zip
+ https://josm.openstreetmap.de/josmfile?page=Styles/MapWithAI&zip=1

Validator rules:
+ https://github.com/Jungle-Bus/transport_mapcss/raw/gh-pages/transport.validator.zip

Last errors/warnings:
- 00005.237 W: Not a single layer for the name 'where apple': []
- 00005.237 W: Not a single layer for the name 'where apple': []
- 00006.211 W: java.io.IOException: The requested URL https://github.com/osmlab/applepaintstyles/archive/master.zip was not found
- 00006.978 W: Failed to load Mappaint styles from 'https://github.com/osmlab/applepaintstyles/archive/master.zip'. Exception was: java.io.IOException: The requested URL https://github.com/osmlab/applepaintstyles/archive/master.zip was not found
- 00006.979 E: java.io.IOException: The requested URL https://github.com/osmlab/applepaintstyles/archive/master.zip was not found
- 00007.494 E: Failed to locate image 'MapWithAI'
- 00143.487 E: Handled by bug report queue: java.lang.IllegalArgumentException: POLYGON cannot have zero area



=== REPORTED CRASH DATA ===
BugReportExceptionHandler#handleException:
No data collected.

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: MVT-downloader-20 (95)
java.lang.IllegalArgumentException: POLYGON cannot have zero area
	at org.openstreetmap.josm.data.imagery.vectortile.mapbox.Geometry.<init>(Geometry.java:86)
	at org.openstreetmap.josm.data.imagery.vectortile.mapbox.Feature.getGeometryObject(Feature.java:172)
	at org.openstreetmap.josm.data.vector.VectorDataStore.lambda$addDataTile$8(VectorDataStore.java:284)
	at java.util.ArrayList.forEach(ArrayList.java:1259)
	at java.util.Collections$UnmodifiableCollection.forEach(Collections.java:1082)
	at org.openstreetmap.josm.data.vector.VectorDataStore.addDataTile(VectorDataStore.java:282)
	at org.openstreetmap.josm.data.imagery.vectortile.mapbox.MVTTile.getData(MVTTile.java:122)
	at org.openstreetmap.josm.data.imagery.vectortile.mapbox.MVTTile.loadImage(MVTTile.java:71)
	at org.openstreetmap.josm.data.imagery.TMSCachedTileLoaderJob.tryLoadTileImage(TMSCachedTileLoaderJob.java:328)
	at org.openstreetmap.josm.data.imagery.TMSCachedTileLoaderJob.loadingFinished(TMSCachedTileLoaderJob.java:210)
	at org.openstreetmap.josm.data.cache.JCSCachedTileLoaderJob.finishLoading(JCSCachedTileLoaderJob.java:265)
	at org.openstreetmap.josm.data.cache.JCSCachedTileLoaderJob.run(JCSCachedTileLoaderJob.java:234)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)

[taylor.smock]

This is probably a spec misread. The v1 spec didn't do a good job of defining polygons (IIRC), while the v2 spec was very specific on there being interior and exterior rings, with interior rings have a surveyor's area of < 0 ("negative") and exterior rings having an area of > 0 ("positive").

Its possible that 0 might be considered a "positive" number in context, but I'll have to see if I can find the polygon with zero area, so I can figure out how its supposed to be displayed.

[Don-vip]

I get the error while downloading ​https://tiles.where.tn/mvt/6/36/25.pbf

Commands:

[
 CommandInteger [type=MoveTo, parameters=[-9, -17]],
 CommandInteger [type=LineTo, parameters=[9, 17, -19, 0]],
 CommandInteger [type=ClosePath]
]

[Don-vip]

In 17994/josm:

see #17177 - see #20971 - MVT robustness, better logs, javadoc

[Don-vip]

New logs:

2021-07-11 03:46:10.567 FINE: JCS - Submitting job for execution for url: https://tiles.where.tn/mvt/6/36/25.pbf
2021-07-11 03:46:11.388 FINE: JCS - starting fetch of url: https://tiles.where.tn/mvt/6/36/25.pbf 
2021-07-11 03:46:11.389 FINE: JCS - Returning object from cache: 20971:https://tiles.where.tn/mvt/{z}/{x}/{y}.pbf/6/36/25
2021-07-11 03:46:11.390 SEVERE: Cannot add vector data for feature Feature [geometry=[CommandInteger [type=MoveTo, parameters=[-9, -17]], CommandInteger [type=LineTo, parameters=[9, 17, -19, 0]], CommandInteger [type=ClosePath, parameters=[]]], geometryType=POLYGON, id=0, ] of tile Tile 6/36/25@20971 [LOADING...] [loaded]: POLYGON cannot have zero area
2021-07-11 03:46:11.401 SEVERE: java.lang.IllegalArgumentException: POLYGON cannot have zero area
java.lang.IllegalArgumentException: POLYGON cannot have zero area
	at org.openstreetmap.josm.data.imagery.vectortile.mapbox.Geometry.<init>(Geometry.java:86)
	at org.openstreetmap.josm.data.imagery.vectortile.mapbox.Feature.getGeometryObject(Feature.java:174)
	at org.openstreetmap.josm.data.vector.VectorDataStore.addFeatureData(VectorDataStore.java:303)
	at org.openstreetmap.josm.data.vector.VectorDataStore.addDataTile(VectorDataStore.java:285)
	at org.openstreetmap.josm.data.imagery.vectortile.mapbox.MVTTile.getData(MVTTile.java:122)
	at org.openstreetmap.josm.data.imagery.vectortile.mapbox.MVTTile.loadImage(MVTTile.java:71)
	at org.openstreetmap.josm.data.imagery.TMSCachedTileLoaderJob.tryLoadTileImage(TMSCachedTileLoaderJob.java:328)
	at org.openstreetmap.josm.data.imagery.TMSCachedTileLoaderJob.loadingFinished(TMSCachedTileLoaderJob.java:210)
	at org.openstreetmap.josm.data.cache.JCSCachedTileLoaderJob.finishLoading(JCSCachedTileLoaderJob.java:265)
	at org.openstreetmap.josm.data.cache.JCSCachedTileLoaderJob.run(JCSCachedTileLoaderJob.java:228)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:833)

My understanding is that your code is correct according to MVT spec and the tile is erroneous. In r17994 I catched the exception to issue an error log and continue with next feature. I'll let you check if the behavior is OK :)

[Don-vip]

I think it's fixed. Please reopen if I did wrong.

[taylor.smock]

I haven't seen anything wrong. :)

Probably the best option was to catch the exception and continue on. That shouldn't affect anything (except not showing a polygon with no area).