Over the past several years my work has been focusing more and more on web GIS applications and I have chosen to use open source technologies rather than commercial applications for several reasons. Continue reading “Five reasons QGIS should be the backbone of your open source web GIS project”
Adding Legends to your Leaflet Web Map
I’ve just added a bonus lecture to my course on client side programming with Leaflet. I had a student ask about creating legends for Leaflet maps and I agreed that this was an important missing piece that I had neglected in the main part of the course. I want this course to be comprehensive and so my intention is to continue adding and updating content as needed to provide the best value for my students. Continue reading “Adding Legends to your Leaflet Web Map”
MapIt. GPS data collection for Android
A few months ago I saw an announcement posted to a GIS user group that I subscribe to. They were looking for someone to spend a month volunteering in Guinea, West Africa to teach a course on soil mapping with GIS and GPS. I am not a soil scientist by any means but I have worked with GIS and GPS for 25 years, mostly in the environmental consulting field and have picked up a bit of knowledge of soils through my work.
For the past several years I have been trying to find a way to use my knowledge of GIS and GPS to provide more benefit to conservation and humanitarian causes in the developing world. I had also recently moved to Mexico to get married and for once was not limited by vacation days, so I decided to answer the call. Continue reading “MapIt. GPS data collection for Android”
Spatial analysis in Leaflet with Turf.js (Part 3 – Line intersection)
In this video I demonstrate how to use Turf.js to return the intersection of lines and polygons. There is not a straightforward way to perform this analysis in Turf.js but Turf.js is better thought of as a toolbox than a packaged solution. And turf.js does provide a number of tools that can be used in conjunction to perform this analysis. Continue reading “Spatial analysis in Leaflet with Turf.js (Part 3 – Line intersection)”
Spatial Analysis in Leaflet using Turf.js (Part 2)
In this video I demonstrate how to use Turf.js to summarize the characteristics of the points inside a polygon using the turf collect method and discuss a couple other relevant methods in turf for dealing with point in polygon type analyses. Continue reading “Spatial Analysis in Leaflet using Turf.js (Part 2)”
Diversity Calculator
Diversity Calculator
The motivation for this software came several years ago when I responded to a request on the Society for Conservation GIS list serve. The issue was the difficulty in summarizing the diversity of a set of species locations as point data over a set of study area polygons. Continue reading “Diversity Calculator”
New Course! Leaflet.js client-side programming.
Display and analyze GIS data on the web with Leaflet.js. For FREE!!!!
This course is available now on Udemy.com. It will show you how to add a web map to a web page using Leaflet.js including
- Geolocation methods
- Native and plugin map controls
- Base maps
- Adding raster data
- Vector layers
- Group layers
- Native leaflet styling options
- Plugin styling options
- Loading GeoJSON files
- Searching
- Filtering
- Nearest feature
- Geoprocessing with Turf.js
Continue reading “New Course! Leaflet.js client-side programming.”
Leaflet Basemaps
One of the reasons to use Leaflet as your JavaScript mapping API is the large number of basemaps available.
This includes very useful basemaps, showing streets, topography, cities, borders, aerial imagery, etc. that you can overlay your data on.
There are also a number of fun and artistic basemaps available, such as the heavy metal themed Spinal Map, artistic water color maps, old-timey pioneer themed maps, and others.
You can see a live version of about 20 of these basemaps at https://millermountain.com/basemap/.
Spatial Analysis in Leaflet using Turf.js
This video explains the basics of Turf.js. Turf.js is a spatial analysis library for JavaScript. You can use Turf.js in web mapping applications to create buffers, intersect and union polygons, dissolve on attributes, perform spatial joins, and much more. Continue reading “Spatial Analysis in Leaflet using Turf.js”
Filtering data in Leaflet
This video shows an example of how to filter data in Leaflet using HTML radio buttons to make a selection. This is analagous to using a definition query in ArcGIS or a filter feature in QGIS. We are limiting which data is included in a feature group based on its attributes. Continue reading “Filtering data in Leaflet”