November 03, 2021

The best Youtube channels in QGIS (and open source GIS tools)

November 03, 2021/ Saul Montoya

Education is aimed to acquire knowledge and it's based on the learning process and as any process has some steps and means that have to be analyzed. Traditionally, if you want to get knowledge you can go to a university, get a degree, visit a library, but why don’t you just check a Youtube channel; will you get the same knowledge? Will you do better research with what you learned on video? Those are excellent questions to pose in these times where we need knowledge that shapes our future in the context of climate change.

June 21, 2021

How to create a point/line/polygon shapefile with Python and Fiona - Tutorial

June 21, 2021/ Saul Montoya

Storage, management and analysis of geospatial vector data as an ESRI shapefile is a common procedure of GIS and related professionals. The generation of these spatial files can be done not only on a desktop software but also by Python commands. We have created an applied example that shows the procedure in Python to create point, line, and polygon shapefiles from a csv file by the use of the Fiona library.

June 18, 2021

How to install Python geospatial libraries (Gdal, Fiona, Rasterio, etc) under a Conda Env in Windows

June 18, 2021/ Saul Montoya

Python is a great tool for spatial analysis and geomachine learning, however sometimes the Windows operating system presents some difficulties to install and run the bunch of Python libraries such as Gdal, Fiona, Geopandas, Rasterio. We are aware that most geoscientists, water resources specialists and related professionals work on Windows, therefore we are always in the search of new ways to get Python working with all its geospatial capabilities in every computer. We have created a tutorial that shows the installation process of the Python geospatial libraries in Windows by the use of a Conda environment; the process is simple on its steps, however the sequence and factors related to the package compatibility are important on the installation.

June 03, 2021

How to extract centroid coordinates in QGIS with Field Calculator - Tutorial

June 03, 2021/ Saul Montoya

We did a simple procedure in QGIS but unknown to us that extracts the centroids of lines and polygons with Field Calculator commands inside the attribute table. The procedure is straightforward and does not involve the use of any intermediate layer.

June 02, 2021

How to install Postgresql and Postgis in Windows 10 with WSL and Debian - Tutorial

June 02, 2021/ Saul Montoya

The normal method to install Postgresql and Postgis requires the set up of several binaries and the workflow is usually on graphical user interfaces (GUI). We wanted to come with a way to install Postgresql and Postgis in Windows 10 while keeping the shell experience from Linux. This tutorial shows the procedure to install the database inside a Debian application (it could be Ubuntu as well) in Windows 10 that can actually be accessible from QGIS.

May 14, 2021

How to make a geological map with QGIS - Tutorial

May 14, 2021/ Saul Montoya

This tutorial deals with the representation of geological information at regional scale from the Central Beaverhead Mountains, Idaho, US and creates a geological map through a series of processing and representation steps as:

Applying styles to geological units
Representation of contacts and normal / thrust faults

May 08, 2021

How to interpolate geospatial points to contours with Python and GDAL - Tutorial

May 08, 2021/ Saul Montoya

We have developed an alternative to a common procedure in GIS that is to create contours from a point shapefile but just with Python commands. By the use of Python and the GDAL library we can store this process into a function and perform contours from several point sets or different point queries.

May 03, 2021

How to make a lake/reservoir volume-elevation curve with Python - Tutorial

May 03, 2021/ Saul Montoya

Python is a programming language capable of performing calculations for hydrological studies and water resources evaluations. We have done a tutorial for the volume-elevation curve determination of the lake Patillas in Puerto Rico with Python and numerical / spatial libraries as Numpy and Rasterio. Finally, results were compared to the volume-elevation curve form a USGS survey. The procedure was done this time for a lake, but can be easily applied to any reservoir or water body when the bottom elevation is available as a raster file.

April 29, 2021

How to make a lake bathymetric map with QGIS - Tutorial

April 29, 2021/ Saul Montoya

Bathymetric data requires some spatial processing to represent lake bottom elevation contours and lake depth. This tutorial shows the complete procedure to analyse a bathymetric survey on the Lake Patillas in Puerto Rico with QGIS to generate:

April 12, 2021

How to display anticlines / synclines in QGIS - Tutorial

April 12, 2021/ Saul Montoya

There are three essential things for the representation of geological data on QGIS: the spatial geological information, an appropriate symbology and the software knowledge. Once these three things are available, the potential of QGIS to represent geological maps is unlimited.

We have done a tutorial for the representation of synclines, anticlines, overturned synclines and overturned anticlines on the regional scale with QGIS.

March 29, 2021

Delineate water bodies (lakes) from Landsat 8 using machine learning with Python and QGIS - Tutorial

March 29, 2021/ Saul Montoya

The process of retrieving information from satellite imagery could be time consuming and faces challenges like image resolution, feature recognition and user criteria. With the use of machine learning tools we can preprocess images and combine them with standard QGIS tools to delineate objects in a much efficient way.

We have done a tutorial for the delimitation of water bodies as lakes from a panchromatic Landsat 8 image. The tutorial shows a mixed procedure that detects edges with Python and Scikit Image , traces paths with QGIS and the Trace Raster plugin and finally gets the lake extension as a Shapefile.

March 16, 2021

How to plot thrust and normal faults in QGIS - Tutorial

March 16, 2021/ Saul Montoya

A good spatial representation of the geological features requires not only high quality field data but also the right symbology and graphical resources. We can define QGIS as the tool that can create awesome geologic maps but still some resources have to be developed for a massive use. This tutorial shows the procedure to represent normal and inverse faults with symbology included on the input data files.

March 10, 2021

How to add a online topography basemap in QGIS - Tutorial

March 10, 2021/ Saul Montoya

Latest developments in QGIS and online services allows us to create amazing maps in less time. Different types of layers are available XYZ tiles as terrain, satellite, road maps. This time we show the procedure to add 2 types of topograpy layers in QGIS 3 behind geological features.

March 07, 2021

How to delineate crop rows with machine learning using Python and Scikit Learn - Tutorial

March 07, 2021/ Saul Montoya

Drone imagery shows us features on the surface with high precision and machine learning tools allows us to understand and get information from those images. We present a tutorial in Python together with Scikit Learn and geospatial libraries that delineates crop rows on a corn field and provides results as a vector spatial file.

February 22, 2021

Tutorial to convert geospatial data (Shapefile) to 3D data (VTK) with Python, Geopandas & Pyvista

February 22, 2021/ Saul Montoya

In our perspective, 3D visualization of geospatial data has been a long desired feature that has been covered in some features from SAGA GIS or in some plugins from QGIS. This time we developed a Python script that converts point / line / polygon ESRI shapefiles (or any vector file) to unstructured grid Vtk format type (Vtu) by the use of the Python libraries Geopandas and Pyvista. The tutorial has files, scripts, and videos that show the whole procedure with some remarks on the software and spatial files and a discussion about the nature of the spatial files that presents some challenges in the data conversion.

February 17, 2021

How to build a Postgis geodabatase with Python and Geoalchemy (with connection to QGIS3) - Tutorial

February 17, 2021/ Saul Montoya

As a peruvian slang the word “chicha” means mixture, but a mixture of a high level of heterogeneity, something like doing a pizza with all the ingredients from your refrigerator. This time we have developed a tutorial with this “chicha” spirit since it combines a database, sql language, a virtualization engine, Python, a variant of SQL Alchemy, port forwarding and connection to QGIS in Windows. Certainly, we are not code developers by nature, but we are pretty happy to have achieved this level of complexity or mixture.

We have developed an applied tutorial for the implementation of a Postgresql database with Postgis enabled on a Docker image. Information about groundwater well locations have been inserted from a CSV file with Python and Geoalchemy and Docker ports have been forwarded and open to be accessible from QGIS in Windows.

February 11, 2021

How to plot the azimuth and dip from a inclined bedding in QGIS 3 - Tutorial

February 11, 2021/ Saul Montoya

QGIS has a wide range of options for the representation of vector data (point, line and polygon) but specific workflows have to be established to apply QGIS in different fields such as Geology. We found that there were few resources about how to plot geological features as bedding planes, faults, synclines and other and we have decided to do a series of tutorials showing those procedures on applied examples.

This time, we have developed a tutorial with the complete procedure to plot the azimuth and dip of bedding planes with QGIS. The tutorial imports a SVG marker that rotates according to a field value while the dip is presented as a label.

February 08, 2021

How to import a Esri style (.style) into QGIS with Slyr - Tutorial

February 08, 2021/ Saul Montoya

Dealing with spatial data in real life implies dealing with styles for vector data and unfortunately, there we find a huge gap between commercial and open source software. There are some tool to overcome these problems as the QGIS plugin Slyr.

This time we have done a tutorial with whole procedure to change the Esri style (.style files) for geological units to a Xml file with Slyr that is applied to the polygon style in QGIS.

February 05, 2021

Watershed and stream network delineation on large scale basins with QGIS 3 - Tutorial

February 05, 2021/ Saul Montoya

The delineation of watersheds and stream networks is one of the most fundamental steps on water resources analysis. Working with QGIS for water resources shows some challenges on the normal water resources workflow since we have to couple raster / vector datasets, coordinate system, and algorithm limitations.

We have developed a tutorial with the whole procedure to create the watershed and stream network on vector format for large scale basins in QGIS 3. Steps range from elevation datasets download for Nasa Earthdata, creating virtual rasters, lower resolution, change coordinate system, fill sinks, create channel networks, calculate upslope area, polygonize rasters and others.

January 28, 2021

Interactive Shapefile exploration in Jupyterlab with Ipyleaflet and Voila - Tutorial

January 28, 2021/ Saul Montoya

Whether you want to explore or visualize a Shapefile without leaving the Jupyterlab environment or you just want a better tool for the spatial representation this tutorial might be of your interest. We have developed an interactive application on Jupyterlab with Ipyleaflet and Voila that represent a selected shapefile on a canvas with options for basemaps, zoom and others.

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