Background Image of a River

Topic | Web Maps

FOSS4G Image Processing

Creating Cloud Optimized GeoTIFFs and Raster Tiles using GDAL and QGIS

This is a talk I gave at the 2021 Ohio GIS Conference. It outlines an open source pipeline for creating Cloud Optimized GeoTIFFs and raster tiles from a collection of TIFF files....

RTK to WGS84

Transforming Coordinates with JavaScript using proj4.js

In my day job we recently completed a project to field locate our water utility assets using a high-accuracy GPS unit. Now that this data is online and accessible in our web maps, our field crews requested a method to locate these assets again using GPS if need be, for instance if there is a foot...

Highlighting Features in Mapbox GL JS

A Comparison of Filter and Feature-State

Creating a hover effect is a great way to add interactivity to web maps. In mapbox-gl there are two main methods to accomplish this feature: setFeatureState() and setFilter(). Up until now (late 2019) I had been using the setFilter method to create a highlig...

CartoDB Visualizations

One Data Set Four Ways

The maps above use the same data set, visualized using four different map types in the CartoDB web interface. The torque map in the header uses the feature id for the time variable so it serves no analytic purpose, but it makes for a nice effect....