11
votes
Accepted
Seeking QGIS geometry generator manual?
There is no such site so far. The feature is rather new and usage examples are only starting to emerge now.
For your specific use case, I'd still recommend to create a line layer with all ...
- 84.5k
11
votes
Latitude, longitude, projections, CRS
Latitude-Longitude coordinates are not projected, they live on an ellipsoid. Occasionally, you'll find lat-lon values referenced to a sphere instead. This ellipsoid is, however, defined by a ...
- 43.1k
10
votes
Seeking tutorials online explaining how to draw squares (having specific length) in QGIS?
When you try to create a new polygon, you can use the Advanced Digitizing, Remember the tool don't work with geographic coordinates.
Click in Toogle Editing.
Click in add polygon feature.
Click in ...
- 928
9
votes
Seeking QGIS geometry generator manual?
This is possible using a different 'geometry generator' to the one that you originally intended I suspect, You can avoid having to generate the all connections line layer by using a virtual layer:
...
- 3,427
8
votes
Button won't work for plug-in in QGIS
You've already defined a SaveAttributesDialog() object in __init__ method and you have set pushButton.clicked event. Because you assign a new SaveAttributesDialog() to self.dlg in add_action method, ...
- 78k
8
votes
Converting Model in Plug-in in QGIS
To create a plugin from a model, use the "Plugin Builder" plugin.
By following THIS tutorial, you can build a basic structure.
On the third screen for plug-in creation, define the template as Process ...
- 1,118
8
votes
Seeking tutorial to split group of layers in QGIS
If you want to create a new group, click on the paper clip icon and create a sub-group, then drag it out of the original group to become a separate group and not sub-group. See the image below. ...
- 41.4k
7
votes
Accepted
Learning JavaScript for GIS?
You could start with this tutorial W3Schools-JavaScript Tutorial
Esri has a good resource in learning through their software - ArcGIS API for JavaScript
Certainly plenty of resources out there to ...
- 12.1k
7
votes
Resources for Arcpy Field Mappings String Syntax
The string you are looking at is the string representation of the field mapping object which is used to map fields when exporting feature classes or when running operations that will combine ...
- 30k
8
votes
Why did Esri create .zlas compressed LiDAR files instead of adopting .laz?
I can see no technical reason for ESRI's creation of zLAS. A decision was made that - as far as I understand - was quite heavily contested even within the ESRI management to create a format under ...
- 1,194
7
votes
Where is QGIS Desktop data stored?
I think you can answer IT that QGIS simply do not store any data, it's a tool that let you access, display, create, analyse and manage data but has no data storage component.
When you access existing ...
- 17.4k
7
votes
Accepted
Difference between control point, reference point, and tie point
You can better understand the difference by taking a hypothetical drone/satellite survey example.
So, in a drone survey, you collect multiple images and process them later.
A tie point is the same ...
- 2,740
6
votes
Accepted
Seeking training plugin for QGIS？
BoundlessGeo developed a plugin called Lessons-plugin.
The description is here: https://github.com/boundlessgeo/qgis-lessons-plugin
I saw the demo, it was pretty nice.
There is a video on it: https://...
- 7,447
5
votes
Accuracy of measurements in Google Earth
In 2011 two brazilians published an article about it, and they concluded that:
*the error is just 0,44% for line measurements;
*the error is just 3,54% for polygon measurements;
*the error is just 1,...
5
votes
Accepted
How could we get presentation of FOSS4Geurope 2017?
The conference website provides a link to a repository with the presentations.
Unfortunately it's hidden behind a link saying "OSGeo Repo for FOSS4G Europe 2017 Conference" which is easy to miss.
...
- 6,569
5
votes
Choosing spatial statistical tool in ArcGIS Desktop?
Spatial Statistics Resources or https://spatialstats.github.io/. This page made in 2010 in the esri blog,But esri update it when a new resource availabled.
The ESRI Guide to GIS Analysis, Volume 2. ...
- 5,835
5
votes
Accepted
How much do leaves on/off affect the number of LiDAR ground returns?
How much do leaves on/off affect the number of LiDAR ground returns?
It does affect significantly. Take a look at Wasser et al. (2013)'s figure 4 (adapted) and see how the frequency of returns are ...
- 10.3k
5
votes
Accepted
Open source desktop GIS for high school curriculum?
If you are interested in a desktop GIS application similar to ArcGIS but open source, QGIS is definitely the way to go.
There are even two books specifically for use in class rooms at https://...
- 84.5k
5
votes
Using WinForms with ArcGIS Pro SDK?
It is technically possible and doable, but building the new ArcGIS Pro .NET Add-in on WPF is the way to go for ArcGIS Pro customizations.
If you are set on embedding WinForms in WPF, you'll use the ...
5
votes
Accepted
Transferring flows (connections and values) between polygons in QGIS
With the Virtual Layers, theoretically, it's possible (with shapefiles, the process will be extra long, but if the layers are in a Spatial Database, I think it is a lot faster).
Here the code :
-- ...
- 15.9k
5
votes
Gdalserver purpose and function
Gdalserver creates a proxy for running some processes in isolated space. It is perhaps best documented in https://www.osgeo.cn/gdal/doxygen/gdal_api_proxy.html.
When dealing with some file formats, ...
- 69k
4
votes
Open Trip Planner Tutorial
I have written a tutorial on using OTP that might be useful:
https://github.com/marcusyoung/otp-tutorial
It's aimed at beginner/intermediate users of OTP (setting up and query an OTP instance, ...
- 61
4
votes
Understanding QGIS API documentation
Actually, QGIS API Documentation (and maybe many API Docs) is written in C++ terminology. At first, users who don't know about C++ find it hard to understand API Docs. However, over time it's getting ...
- 78k
4
votes
Understanding QGIS API documentation
The new official PyQGIS API documentation should take care of this issue since it translates the original C++ code documentation to Python.
- 84.5k
4
votes
Transferring flows (connections and values) between polygons in QGIS
You could do a join between the three layers, then aggregate by layerB. Virtual layers can likely be used. I am not sure if the important data is in layerA or in the flow layer.. Here is an (untested) ...
- 43.1k
4
votes
Where is QGIS Desktop data stored?
QGIS desktop is a software that allows you to visualise, edits and manipulate spatial data and their associated attribute information, it does not come with any dataset per se. You create your own ...
- 667
3
votes
Accepted
Is there any documentation on how to change the user interface of Potree?
The first one is from Potree 1.3, where all the available stuff fit into a dat.gui panel (top-right), whereas the second link is from Potree 1.5RC, where everything has been stacked into the sidebar ...
- 503
3
votes
Free / Open source GIS Education sources
Here is a list of free online GIS courses. It contains courses of different levels, basic to advanced, and there are a few programming options as well.
3
votes
Seeking documentation for {z}/{x}/{y} syntax in tilesource urls?
Short answer:
Nope, it's just a convention.
Long answer:
They're called 'URL templates', and are related to the template processing functionality found in many programming languages. As of ES6 they're ...
- 431
3
votes
Learning Python programming with generic GIS goals in mind?
I am in a similar situation, trying to learn more about programming within an ArcGIS environment.
The best information is all online, learning through practice and examples.
I have slowly increased ...
- 2,291
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