TWiki> IVOA Web>IvoaDataModel>STC>STC-1_33-Errata>STC-1_33-Erratum-2 (2019-05-08, MarkCresitelloDittmar) EditAttach

Author: DM WG

Date last changed: 2018-11-18

Date accepted:2019-04-16

This erratum is to correct an error reported at the IVOA interop in Victoria, BC: May 2018

*Section 4.5.1.4 (pg 30-31: Region.Polygon) states:**"The inside of the region is defined as that part of coordinate space that is encircled by the polygon in a counter-clockwise sense. What this means is that, in a plane, if A > 0, the “inside” of the polygon is included; if A < 0, the “outside” is selected. On a sphere with a left-handed (celestial) coordinate system, if A > 0, one has identified the inside of the polygon; if A < 0, one used the “outside” angles of the polygon and the area is really 4π − A *

This is also wrong because if A < 0 then 4*pi – A is > 4*pi, and that cannot be.

The correct text is:

- Section 4.5.1.4 (pg 30-31: Region.Polygon) :
**if A < 0, one used the “outside” angles of the polygon and the area****is really 4π − A**.

- Software using the wrong formula must be updated

Topic revision: r4 - 2019-05-08 - MarkCresitelloDittmar

**IVOA.net**

Wiki Home

WebChanges

WebTopicList

WebStatistics

**Twiki Meta & Help**

IVOA

Know

Main

Sandbox

TWiki

TWiki intro

TWiki tutorial

User registration

Notify me

**Working Groups**

Data Access

Data Model

GWS

Query Language

Registry

Stds&Procs

Semantics

VOTable

Applications

**Interest Groups**

Data Curation

Theory

Education

Operations

Time Domain

Knowledge Discovery in Database

Solar System

Copyright © 2008-2020 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.

Ideas, requests, problems regarding TWiki? Send feedback

Ideas, requests, problems regarding TWiki? Send feedback