[postgis-tickets] [PostGIS] #3539: geography ST_Segmentize returning straight line instead of curved

[PostGIS]

#3539: geography ST_Segmentize returning straight line instead of curved
----------------------+---------------------------
  Reporter:  robe     |      Owner:  pramsey
      Type:  defect   |     Status:  new
  Priority:  blocker  |  Milestone:  PostGIS 2.3.0
 Component:  postgis  |    Version:  trunk
Resolution:           |   Keywords:
----------------------+---------------------------
Description changed by robe:

Old description:

> This appears to be a new regression which I am not seeing in PostGIS
> 2.2.2 install.
>
> When I tried this query in PostGIS 2.3.0 I'm getting a straight line
> instead of a curve.
>

> {{{
> SELECT ST_AsText(ST_Segmentize(
> ST_MakeLine(ST_Point(-73.8893, 40.6975),
> ST_POINT(72.8667,19.1583))::geography, 10000000)::geometry);
>
> }}}
>
> In 2.2.2 I get this which gets curvier as I reduce the segmentize meters
>

> {{{
> LINESTRING(-73.8893 40.6975,19.6313806536934 62.1086776667385,72.8667
> 19.1583)
> }}}
>

> In POSTGIS="2.3.0dev r14864" GEOS="3.5.0-CAPI-1.9.0 r4088" PROJ="Rel.
> 4.9.1, 04 March 2015" GDAL="GDAL 2.1.0dev, released 2015/99/99"
> LIBXML="2.7.8" LIBJSON="0.12" RASTER I get
>
> {{{
> LINESTRING(-73.8893 40.6975,-0.511300000000007 29.9279,72.8667 19.1583)
> }}}
>

> Look at snapshot for perspective.
>
> [[Image(bad_geog_segmentize.png)]]

New description:

 This appears to be a new regression which I am not seeing in PostGIS 2.2.2
 install.


 When I tried this query in PostGIS 2.3.0 I'm getting a straight line
 instead of a curve.


 {{{
 SELECT ST_AsText(ST_Segmentize(
 ST_MakeLine(ST_Point(-73.8893, 40.6975),
 ST_POINT(72.8667,19.1583))::geography, 10000000)::geometry);

 }}}

 In 2.2.2 I get this which gets curvier as I reduce the segmentize meters
 POSTGIS="2.2.2 r14797" GEOS="3.5.0-CAPI-1.9.0 r4090" PROJ="Rel. 4.9.1, 04
 March 2015" GDAL="GDAL 2.0.2, released 2016/01/26" LIBXML="2.7.8"
 LIBJSON="0.12" RASTER

 {{{
 LINESTRING(-73.8893 40.6975,19.6313806536934 62.1086776667385,72.8667
 19.1583)
 }}}


 In POSTGIS="2.3.0dev r14864" GEOS="3.5.0-CAPI-1.9.0 r4088" PROJ="Rel.
 4.9.1, 04 March 2015" GDAL="GDAL 2.1.0dev, released 2015/99/99"
 LIBXML="2.7.8" LIBJSON="0.12" RASTER I get

 {{{
 LINESTRING(-73.8893 40.6975,-0.511300000000007 29.9279,72.8667 19.1583)
 }}}


 Look at snapshot for perspective.

 [[Image(bad_geog_segmentize.png)]]

--

--
Ticket URL: <https://trac.osgeo.org/postgis/ticket/3539#comment:3>
PostGIS <http://trac.osgeo.org/postgis/>
The PostGIS Trac is used for bug, enhancement & task tracking, a user and developer wiki, and a view into the subversion code repository of PostGIS project.