Re: [Qgis-user] Shifting a Geotiff image
Dear Perth, On 11/08/2023 09:14, Grant Boxer via QGIS-User wrote: I have a GeoTIFF image created using Web ODM and is mis-aligned by 1 to 1.5 m and I would like to move the image to register with the surveyed ground control points. I can see vector tools to do this, but no raster tools. Anyone have any suggestions. If it just a bit off, then the plugin "Freehand raster georeferencer" can be quick to shift it, otherwise use georeferencer from core (Layer - georeferencer), which is especially more flexible and the right tool if you have GCPs that you can use. Be careful, sometimes crashes can occur with certain transformation types, so better save beforehand (autoSaver and MemoryLayerSaver are your friends). Image created in WGS84 z51S. Sound like UTM (good, metric CRS), though WGS84 might be geographic CRS (worse, pixel size undefined/different in x,y). Cheers Martin ___ QGIS-User mailing list QGIS-User@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Non-standard map layout ("projection")
Hello Lester, On 19/04/2023 08:49, Lester Anderson via QGIS-User wrote:> A quick question. Is it possible to project or convert vector data into:> (1) Dymaxion (Fuller Projection)> (2) Watermans Butterfly Projection> (3) Peirce Quincuncial Projection Hormann held a (german) talk and implemented (3) a while ago: https://youtu.be/_i7j2fCeLe8?t=1378 Martin ___ QGIS-User mailing list QGIS-User@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] A few question
On 02.07.20 19:22, blubee blubeeme wrote: > I have some aerial images; Are they georeferenced already? > Warning 4: Failed to open /usr/share/qgis/resources/data/world_map.gpkg: > Permission denied > then one of the below messages for each picture that's being imported. > proj_concatoperation_get_step_count: Object is not a ConcatenatedOperation No issues, no need to act. > Is this just an issue with the images or something wrong my steps to create > orthomosaic from a series of photos. If these are raw photos you need a bundle adjustment/SfM step to generate an orthophoto. This cannot be done 'directly' with gdal. There are some commercial systems and clouds, or you try ODM (Open Drone Map). You may also need ground control points etc. The resulting (georeferenced) orthophoto can be handled in QGIS. ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] wishing for accurate lattitude/longitude from a cell phone
Dear list, I would like to add some things here, since I am trying to use RTK GPS in the field with mobile devices. > 1) Accuracy of GPS Devices RTK GPS or any more precice GPS technology will be external, you cannot get around the missing measurements and lack of algorithms in consumer grade chips. Then it depends on the capabilities of the device to receive satellites of all systems (one or multiple frequencies/signals) and be able to apply correction data (a question of algorithms). For better equipment the prices rise quickly. There are some low cost devices evolving, a new chip was recently announced: Skytraq PX1122R for about $100. Could be tested with a break out board and antenna, e.g. see board at navspark shop. The module even supports PPP, which might be especially interesting where mobile network is not available. https://navspark.mybigcommerce.com/px1122r-evb-px1122r-multi-band-quad-gnss-rtk-evaluation-board/ Other low cost solution were mentioned (emlid/REACH, Catalyst, etc). Am 23.05.20 um 21:51 schrieb Michael.Dodd: > One app that claims to do a lot of what high precions gps does is> Mobile > Topographer Free – Apps on Google Play > 2) Software On Android I was able to get the external signal into the system, you need the app "Bluetoth GPS" (or similar) or a USB2serial + app (better avoid tiny plugs and large cables during field work). Additionally you need to override the internal GPS position with the Blue GPS App in the developer settings (mock provider). My impression was, that most Android applications target the accuracy of the device only, so e.g. * you cannot zoom to cm-levels, only ~100m * not many proper GIS Apps are available, most are expensive * Tracking usually does not rely on cm-grade positions, so the apps are not made for it One particular thing is, that with high accuracy of the signal, an internal computation in single precision float will not suffice (all computations must be in double precision), and you may end up with a cut off of the last position digits, e.g. if you have 8 digits, 4 before and 4 after the decimal separator (e.g. in DDMM. format), then you end up with coordinates cut down to 2-3 decimeters in the real world (typical GPS mouse output, not so uncommon). So, looking into that aspect may be required, and only few Apps may implement that (e.g. expensive "surveyor" apps for professionals? did not test). BTW, sponsoring the double accuracy implementation for QField is welcome, as mentioned ot the webpage. It is already a very usable and FLOSS GIS solution for the field, especially useful if you have a QGIS workflow already ;) Finding proper solutions and recommendations still required... > > *From:* Qgis-user on behalf of > j.hu...@post-ist-da.de > *Sent:* 23 May 2020 20:35 > *To:* qgis-user@lists.osgeo.org > *Subject:* Re: [Qgis-user] wishing for accurate lattitude/longitude from > a cell phone > > > Hi Steve, > > I think there are two different aspects to your question: > 1) Accuracy of GPS Devices > I agree with others that you can't expect a better accuracy than the 10 > to 30 feet you observed with a smartphone or a simple handheld GPS. This > might improve by averaging, but this takes time. Survey grade GPS > devices are very expensive. It is possible to get good modules and > antennas as components, but building a complete GNSS system requires > time and skill. This would reduce cost, but only to several hundred > instead of several thousand dollars, so this is no option in your case. > Besides, you will still need a correction data service (usually costly) > or use two receivers (rover and base). > So you probably have to stick with your phone, which is more flexible > regarding the software than a handheld GPS. > > 2) Software > The accuracy of the recorded position should not depend on where you tap > the screen - a good app should allow to record the current GPS position. > I am using Locus Map (Asamm Software) for a while now, it works quite > well, although it does not allow position averaging. There is a free > version, you could try that first. > > Regards, > Jochen > > Am 22.05.20 um 20:54 schrieb Stephen Sacks: >> >> In order to make widely available some wise advice, I'm sending to >> this list a message I received from Neil B. In addition to Neil's >> message below, I want to mention that Nicolas Cadieux also provided >> similar information, saying I'd have to pay around $1,000 for >> equipment that gives consistently accurate location coordinates. And >> thanks, also to Falk Huettmann and Bernd Vogelgesang for their replies. >> >> >> Message from Neil B: >> >> Hello Stephen. >> Glad that you're having success. I would like to start off by saying >> that it is best to always reply to the mailing list and not directly >> to the person who submitted the email. Mailing lists work really well >> in that there is a pool of people out there
Re: [Qgis-user] About plant count
Hello! Am 02.09.19 um 02:56 schrieb carlos h: > Hello, thank you very much, of course, I have examples, they are images of > Drones in RGB. > > I will attach some images (not the orthomosaic since they are very heavy) > in banana, palm oil and pineapple: > https://www.dropbox.com/sh/42byg669epahkq2/AABhhshbZVJrpJqWnUSEzcBpa?dl=0 If you have RGB images, you could use EGI=2*G-B-R and a threshold to segment plants (if they dont overlap in the image), then count it. But since the plants in your images overlap and other areas are green, too, this might be difficult (you need to find something to segment trees based on other features, e.g. to segment the "star" structure/centers of the trees). Martin ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] [ubuntu] Error when starting QGIS
Am 22.11.18 um 09:47 schrieb psantana: > I installed via apt-get the latest version of QGIS following this > documentation: > https://qgis.org/en/site/forusers/alldownloads.html#debian-ubuntu > > qgis=1:3.4.1+28bionic > ubuntu version: 18.04 > > When starting to start the app I get this exception: > > $ qgis > /usr/bin/qgis.bin: relocation error: > /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5: symbol > _ZTI20QOpenGLShaderProgram version Qt_5 not defined in file libQt5Gui.so.5 > with link time referenc> > I have installed these packages: qgis python-qgis qgis-plugin-grass > > Do you guys know where is the problem? Not exactly, but did you add the ubuntu-gis non-ltr ppa? Below is my qgis.list with all entries to quickly change between LTR and 3.4 versions by switching deb https://qgis.org/ubuntugis xenial main vs. deb https://qgis.org/ubuntugis-ltr xenial main You need also to change xenial to bionic everywhere. After changing the following should remove the deps properly and reinstall the new version: apt update apt remove qgis-common python-qgis qgis-providers-common python-qgis-common qgis-provid er-grass apt autoremove apt install qgis python-qgis qgis-provider-grass qgis-providers more /etc/apt/sources.list.d/qgis.list # ubuntugis unstable deb http://ppa.launchpad.net/ubuntugis/ubuntugis-unstable/ubuntu xenial main deb-src http://ppa.launchpad.net/ubuntugis/ubuntugis-unstable/ubuntu xenial main # Nightly build for Debian and Ubuntu [5] # deb http://qgis.org/debian-nightly xenial main # Nächtliche Paket mit UbuntuGIS Abhängigkeiten # deb http://qgis.org/ubuntugis-nightly xenial main # Long Term Release Repository 2.18.x Las Palmas LTR # Freigabe für Debian und Ubuntu # https://qgis.org/debian-ltr # Release with ubuntugis-unstable dependencies # deb https://qgis.org/ubuntugis-ltr xenial main # Nächtliches Paket des zukünftigen Pointreleases für Debian und Ubuntu # https://qgis.org/debian-nightly-ltr # Nightly build of upcoming point release with ubuntugis-unstable dependencies # https://qgis.org/ubuntugis-nightly-ltr # Latest Release3.2.x Bonn # Freigabe für Debian und Ubuntu # deb https://qgis.org/debian # Release with ubuntugis-unstable dependencies deb https://qgis.org/ubuntugis xenial main # Nächtliches Paket des zukünftigen Pointreleases für Debian und Ubuntu # https://qgis.org/debian-nightly-release # Nightly build of upcoming point release with ubuntugis-unstable dependencies # deb https://qgis.org/ubuntugis-nightly-release xenial main ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Measurement tool
Am 02.11.18 um 13:36 schrieb Josh Hull: > inaccurate measurement when I am measuring both area and straight line > and its using WGS 84 / Pseudo-Mercator. I primarily use the software for > maps in north central United States. Pseudo-mercator might be your issue here, it might have large distortions, since your region is far away from equator. Consider using UTM for metric units and measurements. And have a look for the CRS of your project,according to: https://docs.qgis.org/2.8/en/docs/user_manual/introduction/general_tools.html#measuring ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] QGIS Project
Hello Marco! Am 12.04.2018 um 08:31 schrieb Marco Dinges: > What my question is now about, is that I want to receive position > data (coordinates) from another program (not a GPS) on the raspberry > and track that position on my map. Even better with a visualization > on my desktop. Another thing I want to do is something like a > navigation system, where I can give coordinates to the map and get a > live navigation back from it. > > Is something like pushing your own Position data on the map while > being online generally possible? > > How should I start working on it and where might I find more > Information about that? Sounds like you should look into a gpsd, which usually provides (network) APIs for GPS data, but you should be able to push your own data through it (maybe only geographical coordinates), included tools like gpsfake come to my mind for a quick start. Then you can use the standard GPS input in QGIS (or one of the many other tools able to listen to gpsd). Martin ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Help in Field Calculator
Hi, Am 04.04.2018 um 14:27 schrieb Daniel Alejandro Montecinos Rubilar: > What I try to do is then updated columns in a data layer with > another layer. For example , I have two layers A = Poligono , B = > Points . The layer B contains real values. Then would do two things. > 1. Count how many points of the layers B are within the layer A. 2. > From the points of the layer B that are within the polygon layer A, I > need the sum of their values and paste this sum in a column of > created layer "Count points in polygon" (Vector->analysis tools) and "Join attributes by location" (Processing toolbox->vector general tools) are the operations you seem to be looking for. ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Can't install / use NTv2 grid file.
Hello, Am 26.03.2018 um 12:09 schrieb Jürgen E. Fischer: > On Sat, 24. Mar 2018 at 15:20:01 -0700, tomi_w wrote: >> (http://geodaten.bayern.de/oadownload/bvv_internet/kanu/BY-KanU_Oberfranken_Testdatei_vorlaeufig.zip), >> which I have extracted and copied to /usr/share/proj/oberfranken.gsb. > > The GSBs are not automatically picked up. You'll have to add a row (similar > to > the ones with BETA2007.gsb) to the tbl_datum_transform table in > resources/srs.db or simply rename your grid to BETA2007.gsb. Hm, often you need both transformations, since BETA is for whole Germany, the others locally (often per federal state). I checked in visualisations of differences for the new BWTA2017 of Baden-Württemberg here: https://github.com/Marwe/bwta2017data I sent the following accidentially via PM, just some additional pointers See (in German) http://www.gkg-kassel.de/pdf/Praezise_Transformation_im_QGIS_mit_Batchmodus.pdf for details, you need to add it to qgis' sqlite database of transformations. More related stuff: https://gis.stackexchange.com/questions/50365/projecting-shp-from-gk3-to-utm32-with-beta2007#50384 https://issues.qgis.org/issues/11347 Martin ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Why does this message keeps occuring in QGIS? GEOS geoprocessing error: One or more input features have invalid geometry.
Am 16.01.2018 um 21:05 schrieb David Shi: > It is not merge. I am trying to intersect two vector ShapeFiles. > Each contains a collection of polygons. Each collection of polygons > cover the same geography, but has different boundaries. Can I do > that? Sounds like a classic intersect, did you try that already? You get the combination of the two layers, if you have overlapping polygons with different geometries, then all boundaries are kept and the new polygons are bound by them (likely to be more than in each layer due to combinations). Attributes of both layers are appended. If you get errors due to invalid geometries, well, then correct that beforehand. Martin ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Areal Interpolation in QGIS
Hello! Am 16.01.2018 um 12:53 schrieb David Shi: > Is there any Areal Interpolation code in QGIS? Yes, but it depends on what you have. Activate interpolation plugin and use it. If you have points and want areas from them, try voronoi, if you have two layers you want to combine, there are interpolation or attribute related functions. You see, you need to be more specific or look if the above tool already help. Martin ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] txt to shp
Hello John, Am 04.09.2010 20:58, schrieb john: Hello Gerardo, After seeing how long it takes to load and view a large file in qgis 1.5.0 I see the advantage of using smaller excel files of one or two degrees lon and lat. Do you know of a quick and easy way to join points with attributes of similar values of a txt file into polygons? I do not exactly know what you want: a) You simply cannot store polygons in a table. One thing you could think about: use WKT for the polygon geometry. Even if you have a bunch of point coordinates with the same attribute (identifying the polygon) in the table, the order of them would be important, and each polygon has to start and end within the same point. b) Or do you have *corresponding* points for polygons (one point within polygon)? Intersection/join attributes by location are your friends. c) If you want to join a plain table based on corresponding attributes, you can use join attributes (works only with a layer or dbf so far - you could create it from your data). Is it easier to do it as a cvs text file in excel or once loaded into qgis. Any suggestions will of course be much appreciated. thanks, J.R. Martin signature.asc Description: OpenPGP digital signature ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
