[Qgis-user] results Measure Tool vs. length()

2018-05-17 Thread Michel Stuyts
In the length() function QGIS uses the CRS unit of the layer to calculate the result. When I use for example a layer in a local CRS like EPSG:31370 or EPSG:5439 and a layer in EPSG:3857 (that all use meters as unit) the results are very different (+40% difference). Changing the project CRS makes

[Qgis-user] model built in QGIS2 to be imported in QGIS3

2018-05-17 Thread frippe12573
Hi all, I'm using Qgis3, and I would like to use the models I prepared in the past with Qgis2. I saw that the created files (i.e., .model and .model3) look like different. I presume it is not possible to import the old model file, so that I wonder if there is a way to convert the old file in the n

Re: [Qgis-user] model built in QGIS2 to be imported in QGIS3

2018-05-17 Thread Alexander Bruy
Hi, Processing in QGIS 3 was refactored a lot and many algorithms were changed. So it is not possible to covert old models into new format. You need to recreate it. 2018-05-17 16:47 GMT+03:00 frippe12573 : > Hi all, > > I'm using Qgis3, and I would like to use the models I prepared in the past >

[Qgis-user] Problem georeferencing images in UTM

2018-05-17 Thread Carlos Henrique Grohmann de Carvalho
Hello all I have two pngs of topographic maps from southeastern Brazil (a zip file with images and points is available here: https://www.dropbox.com/ s/mexeh4be46pgsk6/images_georef.zip?dl=0) I'm trying to georeference them, but with partial success only. In this image (https://www.dropbox.com/s/

Re: [Qgis-user] Problem georeferencing images in UTM

2018-05-17 Thread Nicolas Cadieux
Hi, Disable projection on the fly. Make sure the project is in the same CRS as your maps. Nicolas > Le 17 mai 2018 à 12:14, Carlos Henrique Grohmann de Carvalho > a écrit : > > Hello all > > I have two pngs of topographic maps from southeastern Brazil (a zip file with > images and points is

Re: [Qgis-user] Problem georeferencing images in UTM

2018-05-17 Thread Carlos Henrique Grohmann de Carvalho
Thanks Nicolas, but the misalignment still persists. OTF is off, project has same CRS as data (epsg 29192). There is a ~400m difference in the N-S direction. Carlos On Thu, May 17, 2018 at 1:28 PM, Nicolas Cadieux < nicolas.cadi...@archeotec.ca> wrote: > Hi, > Disable projection on the fly. Mak

Re: [Qgis-user] Problem georeferencing images in UTM

2018-05-17 Thread stevejking
When using the georeferencer some of the methods require at least 3 points, even though you might think it not necessary. Otherwise you can get unusual results. Steve -- Sent from: http://osgeo-org.1560.x6.nabble.com/QGIS-User-f4125267.html ___ Qgis-us

Re: [Qgis-user] Problem georeferencing images in UTM

2018-05-17 Thread Nicolas Cadieux
Hi, I am looking at your maps now. If I understand, it works with lat long but not the UTM Coordinates. It could be a mistake in the utm grid. Perhaps one utm grid is in NAD27 and the other in NAD83. That could explain the shift. I will look at it. Nicolas > Le 17 mai 2018 à 12:42, Carlos

Re: [Qgis-user] Problem georeferencing images in UTM

2018-05-17 Thread Nicolas Cadieux
Hi, The utm grid is way off or we have the wrong epsg code. If you geofence using 2 points (linear algo) using a service like google earth, you will see the distortion. The long lat coordinate are probably ok but I did not test them. You can either use the long lat or use more points. With 4

Re: [Qgis-user] Problem georeferencing images in UTM

2018-05-17 Thread Carlos Henrique Grohmann de Carvalho
Thanks for the input Nicolas These are official maps so the utm grid is ok. I figured that I was using a linear transformation, with the option to just create the world file, which works for control points at the corners (lat/long), since the boundaries of the map is defined by latitude/longitude.

Re: [Qgis-user] results Measure Tool vs. length()

2018-05-17 Thread Springfield Harrison
Interesting and alarming observation. And how do those results compare with output from the $length variable? Cheers . . . . . Springfield Samsung Tab 4 On May 17, 2018 5:26 AM, "Michel Stuyts" wrote: > In the length() function QGIS uses the CRS unit of the layer to calculate > the result. Wh

Re: [Qgis-user] Problem georeferencing images in UTM

2018-05-17 Thread listsen
I haven't been able to open the dataset but going through the discussion I would like to offer some assistance since I believe there are some misconceptions here: First, the data has nothing to do with the NAD27 / NAD83 datum's since these are North American datum's and they don't apply I believe

Re: [Qgis-user] results Measure Tool vs. length()

2018-05-17 Thread Michel Stuyts
$length gives the same result as length($geometry) Michel Van: Springfield Harrison [mailto:stellar...@gmail.com] Verzonden: vrijdag 18 mei 2018 2:52 Aan: Michel Stuyts CC: qgis-user Onderwerp: Re: [Qgis-user] results Measure Tool vs. length() Interesting and alarming observation. And how d