topic Re: "Polygon shell has no area" when view added from PostgreSQL in ArcMap Questions

"Polygon shell has no area" when view added from PostgreSQL

ThomasPuthusserry — Fri, 15 May 2020 15:42:00 GMT

I have geojson derived from a catchment API stored in a postgres. Using a st_transform function a geometry field is added in a view as per the code below. The resulting view works fine in QGIS however it fails to load when added to ArcMap /Pro. The issue only happens when features contain complex polygons (donut shapes), no issues when the polygon is simple.

This issue seems recent, as I have been using this for over three years now and always the complex polygons were visible within Arc. as anything changed recently?

I can share actual data if that helps.

CREATE OR REPLACE VIEW public.travel_times_test
AS
WITH data AS (
         SELECT travel_data_new.id,
            travel_data_new.type,
            travel_data_new."time",
            travel_data_new.postcode,
            travel_data_new.project,
            travel_data_new.data::json AS fc
           FROM travel_data_new
        )
SELECT row_number() OVER () AS objectid,
    f.id,
    f.postcode,
    f.type,
    f.project,
    f."time",
    st_transform(st_setsrid(st_geomfromgeojson(f.feat ->> 'geometry'::text), 4326), 3785) AS geom
   FROM ( SELECT json_array_elements(data.fc -> 'features'::text) AS feat,
            data.id,
            data.type,
            data."time",
            data.project,
            data.postcode
           FROM data) f;

ALTER TABLE public.travel_times_test
OWNER TO gwkgis2016;

Re: "Polygon shell has no area" when view added from PostgreSQL

ThomasPuthusserry — Fri, 15 May 2020 15:43:39 GMT

Actually used this method to generate the geometry: Storing GeoJSON FeatureCollection to PostgreSQL with PostGIS? - Geographic Information Systems Stack Exchange

Re: "Polygon shell has no area" when view added from PostgreSQL

Zartico-GIS — Tue, 21 Feb 2023 20:44:41 GMT

SG_ZERO_AREA_POLYGON         (-2032)     Polygon shell has no area

Are you sure this was related to donut shapes and not empty geometries? I am encountering this issue (above code) at a low-percentage rate when dealing with data sourced from Open Street Maps.

When I take a close look at them they all have one thing in common: All x- or y-coordinates of a multi-part polygon share the same value (see image). Thus leading to a line aka empty polygon.

I am trying to insert into a PostgreSQL Enterprise Geodatabase (using st_geometry) but these records fail. Anything I can do here to get them to load in? I.e. casting or transforming...? Thinking of looping through and checking the area value of each polygon within a multi-polygon. If 0, then remove it, so at least the rest of the multi-polygon loads in and it doesn't prevent the whole insert.

Here are a few offenders:

@ThomasPuthusserry