I got a chance to attend the 3rd Annual QGIS User Conference at A Coruña, Spain. This was the meeting point of over 100 QGIS developers, users, and trainers from all over the globe. It was the first time I met the QGIS community in person, including some of the people whose work I have admired for … Continue reading QGIS User Conference 2019
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Convert between UTM and Degree coordinates using Google Spreadsheets
Converting between different coordinate reference systems or projection is a fairly standard feature in a GIS. There are a number of command line tools also available for performing bulk-conversions. cs2cs program, part of the PROJ.4 library is my favorite. Recently, someone presented me with an interesting challenge. They were collecting field data in UTM coordinates and needed … Continue reading Convert between UTM and Degree coordinates using Google Spreadsheets
OpenAQ Workshop Notes
I recently attended the OpenAQ workshop in Delhi . The workshop’s goal was to bring tech, science and media folks working on air quality together and brainstorm how to use open data to tackle air pollution challenges. Below are my notes and links to materials presented during the workshop. Below are my notes and links to materials … Continue reading OpenAQ Workshop Notes
Line Transact Surveys using OpenDataKit(ODK)
This weekend, I got an opportunity to volunteer with a non-profit called Junglescapes. We took a day trip to the Bandipur forest in Karnataka where they have done extensive work in forest restoration. One of their success stories is working with the locals to remove invasive species such as Lantana from the forest. Junglescapes volunteers and … Continue reading Line Transact Surveys using OpenDataKit(ODK)
Creating Geospatial PDFs with GDAL Tools
GeoPDF is a unique data format that brings the portability of PDF to geospatial data. A GeoPDF document can present raster and vector data and preserve the georeference information. This can be a useful format for non-GIS folks to consume GIS data without needing GIS-software. While GeoPDF is a proprietary format, we have a close alternative … Continue reading Creating Geospatial PDFs with GDAL Tools
Geo Data Processing with Mapshaper
Mapshaper is a free and open-source tool that is best known for fast and easy simplification. Other tools for simplification - like QGIS or ogr2ogr - do not preserve topology while simplifying. This means you may get sliver polygons or missing intersections. Mapshaper performs topologically-aware simplification and gives you much more control on the process. Other … Continue reading Geo Data Processing with Mapshaper
Spatial Joins on the Command Line
GDAL and OGR libraries come with handy command-line tools. These tools are quite powerful and can save you a lot of effort if you know how to use them. Here I will show how to use the ogrinfo and ogr2ogr tools to perform spatial joins. A single command can do complex operations on your spatial data and save you a … Continue reading Spatial Joins on the Command Line
