Questions and answers about common geospatial issues.
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”
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
Continue reading “New Course! Leaflet.js client-side programming.”
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/.
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”
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”
This video shows how to load your line and polygon GIS data into a leaflet web map, This requires using the Leaflet.Ajax plug-in. I also demonstrate the basics of styling and filtering line and polygon data. Continue reading “Displaying YOUR GIS data in a leaflet map (pt 2 – lines and polygons)”
This video shows how to export your GIS data to a GeoJSON text file and load it into a leaflet web map, This requires using the Leaflet.Ajax plug-in. I also demonstrate the basics of styling and filtering point data. Continue reading “Displaying YOUR GIS data in a leaflet web map (pt 1- Points)”
How is programming for the web different than programming for a single computer?
If you want to create web GIS applications you need to understand the basics of client-server architecture
What does the client do?
What does the server do?
How do the client and server communicate?
What implications does all of this have for web GIS applications?
The short answer is no. But it will help you more than you can imagine. The GIS world doesn’t need everyone to be coders. Most GIS software is sufficiently complex that one could easily spend their entire careers working with one program and never use all of it, let alone have to improve on it. It would certainly be possible to specialize in a specific aspect of GIS or a specific type of analysis and never learn to write your own code. If the thought of programming sends tremors of fear down your spine, fear not. You will always be needed. Continue reading “Do I need to know how to code to be a GIS professional?”
When most people think about web GIS, they think about publishing a map or a data set for the world to see. That’s certainly part of it, but only a small part. For many years when I would try to sell my employers on the concept of web GIS they would reply “We don’t want everyone to see our proprietary information.” After digging in and learning more on my own I began to realize that there was much more to web GIS than publishing content. Continue reading “Why your organization needs a web GIS strategy.”