Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-25 Thread Carlos Cerdán
And light was done! Objective: to get planimetric-UTM-my-zone areas, in square Km, from a LatLong layer, just at one step: in Fields calculator area( transform( $geometry,'EPSG:4326', 'EPSG:32717' ))/100 Sorry, I was wrong for years, reprojecting layers; deactivating OTF SRC; and using

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-19 Thread Carlos Cerdán
> Under project properties, general tab - change "ellipsoid" to "None /Planimetric". Done, but calculated area is still... geodetic area?. I've tried ArcGIS and, for my GEO layer, It gives me desired area (same as an UTM layer, calculated with OTF off); so, it's me or QGIS, but I can't do this

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-19 Thread Blumentrath, Stefan
...@lists.osgeo.org] On Behalf Of Nyall Dawson Sent: 19. oktober 2016 02:59 To: Carlos Cerdán <sig.up...@gmail.com> Cc: qgis-user <qgis-user@lists.osgeo.org> Subject: Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection? On 19 October 2016 at 02:22, C

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-18 Thread Nyall Dawson
On 19 October 2016 at 02:22, Carlos Cerdán wrote: > It was my fault. I was used to consider plane areas as "correct", forgetting > ellipsoidal areas. So, QGIS give us freedom to calculate planar or > ellipsoidal (geodetical) areas, but we must be careful about settings; Is >

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-18 Thread Carlos Cerdán
It was my fault. I was used to consider plane areas as "correct", forgetting ellipsoidal areas. So, QGIS give us freedom to calculate planar or ellipsoidal (geodetical) areas, but we must be careful about settings; Is not it?. Sometimes, too much freedom is annoying! But, How can I calculate UTM

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-16 Thread Nyall Dawson
On 16 October 2016 at 05:20, Carlos Cerdán wrote: > Hi Nyall (and list) > > A small projecto with UTM and GEO layers can be downloaded from dropbox: > > https://www.dropbox.com/s/c4cfb48r5326vrk/Cajamarca.zip?dl=0 > > Attribute table has the correct area in AreaKm2 field (and

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-16 Thread Nyall Dawson
On 15 October 2016 at 01:49, Andrew wrote: > Nyall, > > in 2.14.6 I get incorrect areas in a layer with CRS 3857 but not with a > layer CRS 26910(UTM 10N). > > With the UTM layer I get different areas with OTR on and off, but the > difference is small and I assume it is just

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-15 Thread Carlos Cerdán
Hi Nyall (and list) A small projecto with UTM and GEO layers can be downloaded from dropbox: https://www.dropbox.com/s/c4cfb48r5326vrk/Cajamarca.zip?dl=0 Attribute table has the correct area in AreaKm2 field (and in these unities). "AreaOTFoff" is the area given by field calculator when "On The

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-14 Thread Blumentrath, Stefan
...@lists.osgeo.org] On Behalf Of Nyall Dawson Sent: 14. oktober 2016 22:16 To: Andrew <amcani...@gmail.com> Cc: qgis-user <qgis-user@lists.osgeo.org> Subject: Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection? On 15 Oct 2016 1:50 AM, "

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-14 Thread Nyall Dawson
On 15 Oct 2016 1:50 AM, "Andrew" wrote: > > Nyall, > > in 2.14.6 I get incorrect areas in a layer with CRS 3857 but not with a layer CRS 26910(UTM 10N). > > With the UTM layer I get different areas with OTR on and off, but the difference is small and I assume it is just due

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-14 Thread Nyall Dawson
On 15 Oct 2016 12:51 AM, "Carlos Cerdán" wrote: > > Hi Nyall > > I'm afraid that 2.16 has still this issue. I've loaded an UTM-17 south layer (my zone) and a Lat-long layer and: > > 1. SRC was seted in UTM > > 2. In UTM layer, if OTF SRC transformation is active, I get

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-14 Thread Andrew
Nyall, in 2.14.6 I get incorrect areas in a layer with CRS 3857 but not with a layer CRS 26910(UTM 10N). With the UTM layer I get different areas with OTR on and off, but the difference is small and I assume it is just due to the different ellipsoids. When calculating area in the field

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-14 Thread Carlos Cerdán
Hi Nyall I'm afraid that 2.16 has still this issue. I've loaded an UTM-17 south layer (my zone) and a Lat-long layer and: 1. SRC was seted in UTM 2. In UTM layer, if OTF SRC transformation is active, I get different area than if it's deactivated. Correct value is the last one. 3. In Lat-long

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-12 Thread Nyall Dawson
On 12 Oct 2016 11:56 PM, "Carlos Cerdán" wrote: > > AFAIK, It also is needed to turn off "on the fly SRC transformation" to get correct area values Or QGIS has fixed this point? Everything should be fixed in recent versions, and I very (VERY) much want to know if any

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-12 Thread Blumentrath, Stefan
when calculating area depending on file type or projection? Hi, You may be calculating square degrees and not metres. It can depend on the crs depending on the tools you are using. Nicolas Le 11 oct. 2016 à 08:54, Martina Schäfer [via OSGeo.org<http://OSGeo.org>] <[hidden email]>

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-12 Thread Carlos Cerdán
AFAIK, It also is needed to turn off "on the fly SRC transformation" to get correct area values Or QGIS has fixed this point? If you can't get correct area values, check out about it 2016-10-12 7:40 GMT-05:00 DelazJ : > Hi, > To complete Nicolas answer, you should

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-12 Thread DelazJ
Hi, To complete Nicolas answer, you should check what are the measurements options set in Project --> Project Properties --> General tab. See also http://docs.qgis.org/2.14/en/docs/user_manual/introduction/general_tools.html#measuring 2016-10-12 14:07 GMT+02:00 Nicolas Cadieux

Re: [Qgis-user] inconsistenty when calculating area depending on file type or projection?

2016-10-12 Thread Nicolas Cadieux
Hi, You may be calculating square degrees and not metres. It can depend on the crs depending on the tools you are using. Nicolas > Le 11 oct. 2016 à 08:54, Martina Schäfer [via OSGeo.org] > a écrit : > > I experienced some confusion with calculation of