<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Hi,</div><div><br></div>Not being a postgis user, I would try <span style="-webkit-text-size-adjust: auto; background-color: rgb(255, 255, 255);">use_spheroid=False just to see if the parameters are taking into account. You could also change the epsg code to one that does not use the WGS84 ellipsoid to see if it changes. I have often played around with parameters just to find out the were skipped over by the code because of an other mutually exclusif parameter (you don’t always get an error). </span><div><span style="-webkit-text-size-adjust: auto; background-color: rgb(255, 255, 255);"><br></span></div><div><span style="-webkit-text-size-adjust: auto; background-color: rgb(255, 255, 255);">Like Nyall says, there might not be a single perfect way to do this and you just have to justify your choices and live with it in the end.</span><div><span style="-webkit-text-size-adjust: auto; background-color: rgb(255, 255, 255);"><br></span><div><span style="-webkit-text-size-adjust: auto; background-color: rgb(255, 255, 255);">Thanks for the précisions below, I had assumed that spheroid was a sphere in this case.</span></div><div><span style="-webkit-text-size-adjust: auto; background-color: rgb(255, 255, 255);"><br></span><div><span style="-webkit-text-size-adjust: auto; background-color: rgb(255, 255, 255);">Good luck<br></span><br><div dir="ltr">Nicolas Cadieux<div><a href="https://gitlab.com/njacadieux">https://gitlab.com/njacadieux</a></div></div><div dir="ltr"><br><blockquote type="cite">Le 6 janv. 2021 à 07:17, Rahkonen Jukka (MML) <jukka.rahkonen@maanmittauslaitos.fi> a écrit :<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><span>Hi,</span><br><span></span><br><span>I did my homework and learned that all spheroids are ellipsoids but not all ellipsoids are spheroids. This source puts it into a compact sentence elearning.algonquincollege.com/coursemat/viljoed/gis8746/concepts/geodesy/spheroid.htm</span><br><span></span><br><span>"Ellipsoid is a solid for which all plane sections through one axis are ellipses and through the other are ellipses or circles. If any two of the three axes of that ellipsoid are equal, the figure becomes a spheroid (ellipsoid of revolution). If all three are equal, it becomes a sphere."</span><br><span></span><br><span>The geodetic ellipsoids have two axis with equal length and the third axes is shorter. Therefore in this context terms ellipsoid and spheroid can be used interchangeably https://support.esri.com/en/technical-article/000006398. A tri-axial ellipsoid (https://en.wikipedia.org/wiki/Ellipsoid) is the only sort of ellipsoids that is not spheroid by the same but we do not use such as Earth surface models.</span><br><span></span><br><span>So back to the test. I have the QGIS project in EPSG:4326, the layer in EPSG:4326, and the Project-Properties-General-Measurement-Ellipsoid is set to WGS 84 (EPSG:7030). The $area function returns</span><br><span>249566957499.7546</span><br><span></span><br><span>The ST_Area function of PostGIS https://postgis.net/docs/ST_Area.html with option "use_spheroid=true" returns</span><br><span>251199344354.4308</span><br><span></span><br><span>I modified my SQL to ensure that the geography type is using the WGS 84 spheroid/ellipsoid by adding a cast from EPSG:4326 geometry into geography (reference https://postgis.net/docs/postgis_usage.html#PostGIS_Geography). That did not change the result so obviously WGS 84 spheroid/ellipsoid is the default for PostGIS geography type.</span><br><span></span><br><span>My SQL is now</span><br><span>select ST_Area(ST_GeomFromText('POLYGON ((</span><br><span> 20.13293641 59.95688345,</span><br><span> 26.94617837 60.47397663,</span><br><span> 29.74782155 62.56499443,</span><br><span> 27.45254202 68.70650340,</span><br><span> 23.75771765 68.24937206,</span><br><span> 25.42698984 65.27444593,</span><br><span> 21.51545237 63.10353609,</span><br><span> 21.40562760 61.12318104,</span><br><span> 19.41123592 60.40477513,</span><br><span> 20.13293641 59.95688345))',4326)::geography , true)</span><br><span></span><br><span>I have done my best to force both software to make an ellipsoidal/spheroidal area measurement (not spherical) on WGS 84 ellipsoid/spheroid. This is my informed choice, please point where is the mistake if I have done such.</span><br><span></span><br><span>If I have used the right methods with both QGIS and PostGIS then there is still this 0.654% difference in the measured areas. It feels a bit too large to be caused only by minor differences in implementations if the mathematics is the same. Could it possibly mean that either PostGIS or QGIS computes the area wrong?</span><br><span></span><br><span>-Jukka Rahkonen-</span><br><span></span><br><span>-----Alkuperäinen viesti-----</span><br><span>Lähettäjä: Nyall Dawson <nyall.dawson@gmail.com> </span><br><span>Lähetetty: tiistai 5. tammikuuta 2021 23.46</span><br><span>Vastaanottaja: Rahkonen Jukka (MML) <jukka.rahkonen@maanmittauslaitos.fi></span><br><span>Kopio: Nicolas Cadieux <njacadieux.gitlab@gmail.com>; qgis-user@lists.osgeo.org</span><br><span>Aihe: Re: [Qgis-user] Confusion with ellipsoidal method of $area</span><br><span></span><br><span>On Wed, 6 Jan 2021 at 07:40, Rahkonen Jukka (MML) <jukka.rahkonen@maanmittauslaitos.fi> wrote:</span><br><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Hi,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Sorry, I am amateur on this area and I do not know what is the difference between spheroids and ellipsoids. Do you mean that QGIS is using more accurate method than PostGIS for calculating the lengths and areas over the WGS 84 ellipsoid?</span><br></blockquote><span></span><br><span>You're definitely not alone in this, but I'd strongly recommend doing a bit of research into the differences and how they affect measurements. There's no single "right" answer to how things should be accurately measured, so the decisions regarding this are the user's responsibility, and it's up to you to make an informed choice here.</span><br><span></span><br><span>Suffice to say that both QGIS and geographiclib can do either spherical or ellipsoidal calculations -- to compare them you need to ensure that the exact same sphere/ellipsoid parameters are used.</span><br><span></span><br><span>Nyall</span><br><span></span><br><span></span><br><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>The article that is used as a reference on the GeographicLib page </span><br></blockquote><blockquote type="cite"><span>(Charles F. F. Karney, Algorithms for geodesics,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>J. Geodesy 87(1), 43–55 (Jan. 2013) does not use word spheroid in the text at all but ellipsoid appears there 29 times. So perhaps the library deals actually with ellipsoid but PostGIS and Spatialite documentation talks about spheroid?</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Could you give one linestring and one polygon as reference geometries and the most accurate lengths and areas that you know for some of your favorite ellipsoids to be used as true values?</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>-Jukka Rahkonen-</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Lähettäjä: Nicolas Cadieux <njacadieux.gitlab@gmail.com></span><br></blockquote><blockquote type="cite"><span>Lähetetty: tiistai 5. tammikuuta 2021 22.52</span><br></blockquote><blockquote type="cite"><span>Vastaanottaja: Rahkonen Jukka (MML) </span><br></blockquote><blockquote type="cite"><span><jukka.rahkonen@maanmittauslaitos.fi>; qgis-user@lists.osgeo.org</span><br></blockquote><blockquote type="cite"><span>Aihe: Re: [Qgis-user] Confusion with ellipsoidal method of $area</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Hi,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>QGIS is currently built on Proj version 6.3.2-1. If the other libraries are using a spheroid by default, then they use a sphere for speed and not an ellipsoid for precision. You can probably force this measurement in QGIS by creating a custom CRS with a spheroid rather than an ellipsoid. The other option is to use the python in QGIS and to force a geoid.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Nicolas</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>On 2021-01-05 1:33 p.m., Rahkonen Jukka (MML) wrote:</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Hi,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>I suppose that PostGIS is using the WGS 84 ellipsoid but I am not sure where from the documentation I could find that information. The ST_Area document https://postgis.net/docs/ST_Area.html says only “For geography types by default area is determined on a spheroid with units in square meters”. Same thing with Spatialite, documentation suggests just that it is “the” spheroid http://www.gaia-gis.it/gaia-sins/spatialite-sql-latest.html.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>I did not notice this paragraph in the ST_Area document earlier “Enhanced: 2.2.0 - measurement on spheroid performed with GeographicLib for improved accuracy and robustness. Requires Proj >= 4.9.0 to take advantage of the new feature.” So no wonder that the web app and PostGIS give the same results because they both use GeographicLib. And SpatiaLite 5.0 is using RTTopo that is a library that is based on LWGeom so close connection in there too.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>So perhaps the way to get identical areas from QGIS would be to make it to use GeographicLib as well. I have no idea if it is a realistic approach and worth making a feature request.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>-Jukka Rahkonen-</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Lähettäjä: Nicolas Cadieux <njacadieux.gitlab@gmail.com></span><br></blockquote><blockquote type="cite"><span>Lähetetty: tiistai 5. tammikuuta 2021 20.04</span><br></blockquote><blockquote type="cite"><span>Vastaanottaja: Rahkonen Jukka (MML) </span><br></blockquote><blockquote type="cite"><span><jukka.rahkonen@maanmittauslaitos.fi>; qgis-user@lists.osgeo.org</span><br></blockquote><blockquote type="cite"><span>Aihe: Re: [Qgis-user] Confusion with ellipsoidal method of $area</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Hi,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Your method in QGIS is sound. Area is calculated using the wgs84 ellipsoid EPSG 7030. If you reproject to wgs84 zone 35N (I think this is close), area goes from 249566957499.7546m2 to 249566957499.721m2 or a difference of 0.0336 m2. I don't think densification would change things much.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>My question is the following: You know that QGIS uses the WGS84 Ellipsoid. What Ellipsoid are using used in the other software??? If you don't know, I would proceed until you figure that out.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>This is the currently used ellipsoid in the proj database in QGIS 3.16. You can get this by typing proj -le in the OSFeo4W Shell.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span> MERIT a=6378137.0 rf=298.257 MERIT 1983</span><br></blockquote><blockquote type="cite"><span> SGS85 a=6378136.0 rf=298.257 Soviet Geodetic System 85</span><br></blockquote><blockquote type="cite"><span> GRS80 a=6378137.0 rf=298.257222101 GRS 1980(IUGG, 1980)</span><br></blockquote><blockquote type="cite"><span> IAU76 a=6378140.0 rf=298.257 IAU 1976</span><br></blockquote><blockquote type="cite"><span> airy a=6377563.396 rf=299.3249646 Airy 1830</span><br></blockquote><blockquote type="cite"><span> APL4.9 a=6378137.0 rf=298.25 Appl. Physics. 1965</span><br></blockquote><blockquote type="cite"><span> NWL9D a=6378145.0 rf=298.25 Naval Weapons Lab., 1965</span><br></blockquote><blockquote type="cite"><span> mod_airy a=6377340.189 b=6356034.446 Modified Airy</span><br></blockquote><blockquote type="cite"><span> andrae a=6377104.43 rf=300.0 Andrae 1876 (Den., Iclnd.)</span><br></blockquote><blockquote type="cite"><span> danish a=6377019.2563 rf=300.0 Andrae 1876 (Denmark, Iceland)</span><br></blockquote><blockquote type="cite"><span> aust_SA a=6378160.0 rf=298.25 Australian Natl & S. Amer. 1969</span><br></blockquote><blockquote type="cite"><span> GRS67 a=6378160.0 rf=298.2471674270 GRS 67(IUGG 1967)</span><br></blockquote><blockquote type="cite"><span> GSK2011 a=6378136.5 rf=298.2564151 GSK-2011</span><br></blockquote><blockquote type="cite"><span> bessel a=6377397.155 rf=299.1528128 Bessel 1841</span><br></blockquote><blockquote type="cite"><span> bess_nam a=6377483.865 rf=299.1528128 Bessel 1841 (Namibia)</span><br></blockquote><blockquote type="cite"><span> clrk66 a=6378206.4 b=6356583.8 Clarke 1866</span><br></blockquote><blockquote type="cite"><span> clrk80 a=6378249.145 rf=293.4663 Clarke 1880 mod.</span><br></blockquote><blockquote type="cite"><span>clrk80ign a=6378249.2 rf=293.4660212936269 Clarke 1880 (IGN).</span><br></blockquote><blockquote type="cite"><span> CPM a=6375738.7 rf=334.29 Comm. des Poids et Mesures 1799</span><br></blockquote><blockquote type="cite"><span> delmbr a=6376428. rf=311.5 Delambre 1810 (Belgium)</span><br></blockquote><blockquote type="cite"><span> engelis a=6378136.05 rf=298.2566 Engelis 1985</span><br></blockquote><blockquote type="cite"><span> evrst30 a=6377276.345 rf=300.8017 Everest 1830</span><br></blockquote><blockquote type="cite"><span> evrst48 a=6377304.063 rf=300.8017 Everest 1948</span><br></blockquote><blockquote type="cite"><span> evrst56 a=6377301.243 rf=300.8017 Everest 1956</span><br></blockquote><blockquote type="cite"><span> evrst69 a=6377295.664 rf=300.8017 Everest 1969</span><br></blockquote><blockquote type="cite"><span> evrstSS a=6377298.556 rf=300.8017 Everest (Sabah & Sarawak)</span><br></blockquote><blockquote type="cite"><span> fschr60 a=6378166. rf=298.3 Fischer (Mercury Datum) 1960</span><br></blockquote><blockquote type="cite"><span> fschr60m a=6378155. rf=298.3 Modified Fischer 1960</span><br></blockquote><blockquote type="cite"><span> fschr68 a=6378150. rf=298.3 Fischer 1968</span><br></blockquote><blockquote type="cite"><span> helmert a=6378200. rf=298.3 Helmert 1906</span><br></blockquote><blockquote type="cite"><span> hough a=6378270.0 rf=297. Hough</span><br></blockquote><blockquote type="cite"><span> intl a=6378388.0 rf=297. International 1909 (Hayford)</span><br></blockquote><blockquote type="cite"><span> krass a=6378245.0 rf=298.3 Krassovsky, 1942</span><br></blockquote><blockquote type="cite"><span> kaula a=6378163. rf=298.24 Kaula 1961</span><br></blockquote><blockquote type="cite"><span> lerch a=6378139. rf=298.257 Lerch 1979</span><br></blockquote><blockquote type="cite"><span> mprts a=6397300. rf=191. Maupertius 1738</span><br></blockquote><blockquote type="cite"><span> new_intl a=6378157.5 b=6356772.2 New International 1967</span><br></blockquote><blockquote type="cite"><span> plessis a=6376523. b=6355863. Plessis 1817 (France)</span><br></blockquote><blockquote type="cite"><span> PZ90 a=6378136.0 rf=298.25784 PZ-90</span><br></blockquote><blockquote type="cite"><span> SEasia a=6378155.0 b=6356773.3205 Southeast Asia</span><br></blockquote><blockquote type="cite"><span> walbeck a=6376896.0 b=6355834.8467 Walbeck</span><br></blockquote><blockquote type="cite"><span> WGS60 a=6378165.0 rf=298.3 WGS 60</span><br></blockquote><blockquote type="cite"><span> WGS66 a=6378145.0 rf=298.25 WGS 66</span><br></blockquote><blockquote type="cite"><span> WGS72 a=6378135.0 rf=298.26 WGS 72</span><br></blockquote><blockquote type="cite"><span> WGS84 a=6378137.0 rf=298.257223563 WGS 84</span><br></blockquote><blockquote type="cite"><span> sphere a=6370997.0 b=6370997.0 Normal Sphere (r=6370997)</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Nicolas</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>On 2021-01-05 11:43 a.m., Rahkonen Jukka (MML) wrote:</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Hi,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>I wonder what method QGIS is using when it computes ellipsoidal area with $area function. I made a test with this EPSG:4326 polygon:</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>POLYGON (( 20.13293641 59.95688345, 26.94617837 60.47397663, </span><br></blockquote><blockquote type="cite"><span>29.74782155 62.56499443, 27.45254202 68.7065034, 23.75771765 </span><br></blockquote><blockquote type="cite"><span>68.24937206, 25.42698984 65.27444593, 21.51545237 63.10353609, </span><br></blockquote><blockquote type="cite"><span>21.4056276 61.12318104, 19.41123592 60.40477513, 20.13293641 </span><br></blockquote><blockquote type="cite"><span>59.95688345 ))</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>I checked that the CRS of the project and layer were both EPSG:4326. </span><br></blockquote><blockquote type="cite"><span>The ellipsoid in the Project-Settings was WGS 84 (EPSG:7030). The area </span><br></blockquote><blockquote type="cite"><span>that $area returns is</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>249566957499.7546</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>As a references I used PostGIS and web site https://geographiclib.sourceforge.io/scripts/geod-calc.html#area. With my test polygon they both give this result:</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>251199344354.4308</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>PostGIS returns bigger area. The difference is 0.654% so not huge but not negligible either.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>A third test with SpatiaLite 5.0 gives a result that is very close to PostGIS (difference 0.001%).</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>251195856999.549927</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>As a conclusion I have decided to trust in PostGIS because it gives the same results than the web site https://geographiclib.sourceforge.io/scripts/geod-calc.html that feels scientifically sound. However, I wonder if I have used QGIS in a correct way or if there is anything I could do for getting areas to match better with PostGIS for example by densifying the long segments in my test polygon.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>For getting testing easy I attach directly runnable SQL for PostGIS and Spatialite (version 5.0 with RTTopo is needed) as well as a coordinate list for the web app.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>PostGIS</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>select st_area(st_geogfromtext('POLYGON ((</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>20.13293641 59.95688345,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>26.94617837 60.47397663,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>29.74782155 62.56499443,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>27.45254202 68.70650340,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>23.75771765 68.24937206,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>25.42698984 65.27444593,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>21.51545237 63.10353609,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>21.40562760 61.12318104,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>19.41123592 60.40477513,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>20.13293641 59.95688345))') , true);</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Spatialite</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>select st_area(st_geomfromtext('POLYGON ((</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>20.13293641 59.95688345,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>26.94617837 60.47397663,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>29.74782155 62.56499443,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>27.45254202 68.70650340,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>23.75771765 68.24937206,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>25.42698984 65.27444593,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>21.51545237 63.10353609,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>21.40562760 61.12318104,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>19.41123592 60.40477513,</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>20.13293641 59.95688345))') ,true);</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Web site (notice lat-lon order)</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>59.95688345 20.13293641</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>60.47397663 26.94617837</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>62.56499443 29.74782155</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>68.70650340 27.45254202</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>68.24937206 23.75771765</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>65.27444593 25.42698984</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>63.10353609 21.51545237</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>61.12318104 21.40562760</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>60.40477513 19.41123592</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>59.95688345 20.13293641</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>-Jukka Rahkonen-</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>_______________________________________________</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Qgis-user mailing list</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Qgis-user@lists.osgeo.org</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>List info: https://lists.osgeo.org/mailman/listinfo/qgis-user</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>--</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Nicolas Cadieux</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>https://gitlab.com/njacadieux</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>--</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Nicolas Cadieux</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>https://gitlab.com/njacadieux</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>_______________________________________________</span><br></blockquote><blockquote type="cite"><span>Qgis-user mailing list</span><br></blockquote><blockquote type="cite"><span>Qgis-user@lists.osgeo.org</span><br></blockquote><blockquote type="cite"><span>List info: https://lists.osgeo.org/mailman/listinfo/qgis-user</span><br></blockquote><blockquote type="cite"><span>Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user</span><br></blockquote></div></blockquote></div></div></div></div></body></html>