Re: [Qgis-user] Geometry errors while polygonizing raster data
Correction: The version I am using is 3.4 LTS. On Fri, Apr 10, 2020 at 9:23 PM Atharva Raykar wrote: > Hello, > > I have been trying to convert this raster data using QGIS's Polygonize > function: https://daac.ornl.gov/VEGETATION/guides/Decadal_LULC_India.html > > The converted geopackage is returning many geometries with negative areas. > So much so that the data is highly inaccurate, and some categories are > having negative areas with x^10 sq. meters in magnitude. > > The features basically resemble the ones I found in this stack overflow > answer: https://gis.stackexchange.com/a/243707/161470 , where the holes > are located outside the geometry and are larger than the geometry itself. > > How do I troubleshoot this? Is this a bug with QGIS? > > I'm using QGIS 3.14 LTS. > > > ___ 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
[Qgis-user] Geometry errors while polygonizing raster data
Hello, I have been trying to convert this raster data using QGIS's Polygonize function: https://daac.ornl.gov/VEGETATION/guides/Decadal_LULC_India.html The converted geopackage is returning many geometries with negative areas. So much so that the data is highly inaccurate, and some categories are having negative areas with x^10 sq. meters in magnitude. The features basically resemble the ones I found in this stack overflow answer: https://gis.stackexchange.com/a/243707/161470 , where the holes are located outside the geometry and are larger than the geometry itself. How do I troubleshoot this? Is this a bug with QGIS? I'm using QGIS 3.14 LTS. ___ 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
[Qgis-user] Pavement defects Identification
Hello, Is it possible to identify the pavement defects using a raster image with QGIS? If there is any tutorial about this, can you please direct me the tutorial. Regards. ___ 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 Server and webmapping information
Thanks, I'll check it out. I haven't checked too much the WFS3 yet. Le ven. 10 avr. 2020 à 15:14, Alessandro Pasotti a écrit : > On Fri, Apr 10, 2020 at 3:05 PM Etienne Trimaille > wrote: > > > > Hi, > > > > qgis2web will generate a static website that you can easily move on a > server somewhere, without the need to install QGIS Server. > > The website will be generated from the plugin itself. > > > > If you install QGIS Server only, you will have only some OGC streams > such as WMS, WFS etc. It's just to publish "data" on the internet. But you > won't have the web viewer in an internet browser. > > Then you need to code the web application using Leaflet or OpenLayers. > > That's not entirely correct anymore because WFS3 provides a very > simple browsable website, see > > https://docs.qgis.org/3.10/en/docs/user_manual/working_with_ogc/server/services.html#wfs3-ogc-api-features > > You could easily override the default HTML templates to show your WMS > layers too, no need to rebuild or compile anything. > > Cheers > > > > > -- > Alessandro Pasotti > w3: www.itopen.it > ___ 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 Server and webmapping information
On Fri, Apr 10, 2020 at 3:05 PM Etienne Trimaille wrote: > > Hi, > > qgis2web will generate a static website that you can easily move on a server > somewhere, without the need to install QGIS Server. > The website will be generated from the plugin itself. > > If you install QGIS Server only, you will have only some OGC streams such as > WMS, WFS etc. It's just to publish "data" on the internet. But you won't have > the web viewer in an internet browser. > Then you need to code the web application using Leaflet or OpenLayers. That's not entirely correct anymore because WFS3 provides a very simple browsable website, see https://docs.qgis.org/3.10/en/docs/user_manual/working_with_ogc/server/services.html#wfs3-ogc-api-features You could easily override the default HTML templates to show your WMS layers too, no need to rebuild or compile anything. Cheers -- Alessandro Pasotti w3: www.itopen.it ___ 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 Server and webmapping information
Hi, qgis2web will generate a static website that you can easily move on a server somewhere, without the need to install QGIS Server. The website will be generated from the plugin itself. If you install QGIS Server only, you will have only some OGC streams such as WMS, WFS etc. It's just to publish "data" on the internet. But you won't have the web viewer in an internet browser. Then you need to code the web application using Leaflet or OpenLayers. If you use QGIS Web Client, Lizmap or similar, the web application is already there and will offer some widgets and some tools. It will try to mimic the QGIS Desktop application with the layer tree, the print layouts, dataviz etc. I tried to make this schema : https://docs.lizmap.com/next/en/introduction.html I hope it can help you. There are a few QGIS web applications : QGIS Web Client, Lizmap, GisQuick, Mappia Le ven. 10 avr. 2020 à 14:04, Franko Naimarevic a écrit : > Hello, > > I'm a final-year architecture student, and as part of my thesis, I'm > researching on how to publish a map made in QGIS on the internet, in > hopes of doing so later myself. > I've heard that the qgis2web plugin was a great option, but I've also > found that it was possible to do with QGIS Server. However, I haven't > managed to find a lot of "theoretical" explanations about it, plus, I'm > really not that familiar with this webmapping/GIS "world". So, I was > hoping someone could clarify things for me, as completely as possible. > > I understand the main step is to install it on a server, obviously. But > what are the other things that have to be done in order to publish an > interactive QGIS map on the internet? > > For example, I'm wondering at what point are the widgets (for > navigation, search bar, ...) defined to appear on the webpage? > > Also, QGIS Server and QGIS Web Client seem to work together ; what is > their role in that relationship? Is it a necessity? > > > Thanks in advance for your help, > > Franko > > > > > ___ > 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 ___ 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
[Qgis-user] QGIS Server and webmapping information
Hello, I'm a final-year architecture student, and as part of my thesis, I'm researching on how to publish a map made in QGIS on the internet, in hopes of doing so later myself. I've heard that the qgis2web plugin was a great option, but I've also found that it was possible to do with QGIS Server. However, I haven't managed to find a lot of "theoretical" explanations about it, plus, I'm really not that familiar with this webmapping/GIS "world". So, I was hoping someone could clarify things for me, as completely as possible. I understand the main step is to install it on a server, obviously. But what are the other things that have to be done in order to publish an interactive QGIS map on the internet? For example, I'm wondering at what point are the widgets (for navigation, search bar, ...) defined to appear on the webpage? Also, QGIS Server and QGIS Web Client seem to work together ; what is their role in that relationship? Is it a necessity? Thanks in advance for your help, Franko ___ 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] ISSUE QGIS keeps freezing - QGIS Desktop 3.10.4
Hi Koos - From your description I suspect you had a memory issue, i.e running out of memory. It might be caused by QGIS but it's probably caused by some other app running on your computer. Some (badly implemented) apps are "leaking" memory, i.e: allocating memory, but never deallocating it after use. After some time the bad app has allocated large amounts of memory that's not available to other apps. If you are short on available memory on the computer the OS will begin to swap contents from the memory to and from a swap-file usually placed in the root of C: (the hard-disk containing the OS). This can explain the sudden periodic "freezing" of QGIS: The OS has to load pieces of out-swapped QGIS content into memory before QGIS can continue. If you additionally are short on available disk space on the system drive and are creating some largish temp files (which usually is placed on the system drive), the situation can rapidly escalate to a system crash (BSOD) To avoid this situation: * Install more memory on your computer. * Only have a minimum of apps running at the same time. * Frequently reboot you computer (It's Windows, after all :-) * If you have two hard-disks on your computer: Move the temp directory to different drive than the one containing the swap-file. You already done the "right now"- steps anyway so the mail is more a reminder for other readers or google-searches :-) And by the way: QGIS and Postgres/PostGIS is a killer combination :-) . IMHO it beats other GIS applications hands down. -- Med venlig hilsen / Kind regards Bo Victor Thomsen Den 10-04-2020 kl. 08:55 skrev Koos Fransen: Dear Bo and Andreas Thank you very much for your insights. Given the fact that QGIS has been more stable since yesterday, I think the problem was related to my hard drive memory and temporary files. I did not have a lot of space left on the hard drive, and I tend do leave my computer on when calling it a day, so maybe that combination was not very helpful for QGIS to work smoothly. I’ve deleted some data on my laptop, thus freeing up some space and, as you said, I deleted my temp files for QGIS (I had been working with very large datasets), and for now everything works quite well. I’ll also start shutting off my laptop from time to time 😉 I’ll keep you posted if it should occur again and if I can find a clear solution to the problem. Anyway, Bo, you and your wife’s list is a very good starting point to start problem solving with should this issue occur again. There are some things that I can exclude as reason (build is the stable 3.10 version, it’s not the anti-virus, it’s not a work network environment, …), and some things that I still have to test. Many thanks for your help (and good luck with the teaching assignment, I’m teaching introductory courses in GIS at Vrije Universiteit Brussel, but one of the next things I would like to dive into is the use of PostGIS and PostgreSQL for my own research)! Kind regards Koos -- *dr. Koos Fransen* Research unit Cosmopolis (VUB) Research unit ISE (UGent)** I am available for _VUB_ on _Tuesdays, Thursdays and Fridays_ and for UGent on Mondays and Wednesdays. Consequently, I try to structure meetings accordingly and answers to your mails may be delayed. *From:*Andreas Neumann *Sent:* donderdag 9 april 2020 17:27 *To:* Bo Victor Thomsen ; Koos Fransen ; qgis-user@lists.osgeo.org *Subject:* Re: [Qgis-user] ISSUE QGIS keeps freezing - QGIS Desktop 3.10.4 Hi, These are all good points. I also had severe issues with Antivirus - it slowed down or prevented a lot of the network access. The IT services had to add exceptions. But you describe that it only happens after a couple of days of usage, which is strange. If you find out what the issues really is, please let us know, so we can learn. Andreas Am 09.04.20 um 15:20 schrieb Bo Victor Thomsen: Hi Koos - I had a talk with my wife Lene Fischer about your issues. (She is a Assoc. Prof. teaching GIS at a department of the University of Copenhagen using QGIS. I co-lecture with her on the use of spatial enabled databases (PostgreSQL/ PostGIS)). She hasn't experienced the issues you describe (but some other issues) Here is some pointers: * Use a long-term releases and keep up with the point releases 3.10.3 -> 3.10.4 (Which you do :-) * Clean the temp dir regularly (Which you did :-) * Check the setup of your windows pointers to user-dirs, temp space. Sometimes they are not suited for computers outside the university network (or inside, if the network sucks) * Check if your logon name contains special characters outside us-ASCII like accented character or blanks. QGIS is fine with these but some add-on libraries is not. The logon name can be a part of a path name that something chokes on. * Check your antivirus by temporarily disable it b
