Who is JSON and why does he sometimes have a GEO? An exploration of web mapping file types

Written by Sarah Dewees

So I'm not a computer person and I don't know code, but I want to make maps that people can interact with.  And so far my foray into web mapping has left me a bit lost. I need to know a new language or two ( Java script, css, html) and even some of the words that are in English don't make sense. There seem to be few programs out there to help us illiterate folks code, but you have to be able to get your data onto their server. There are so many file types available and at the same time so many that are unavailable. The questions I hope to answer for myself and graciously share with you are; which file type is best? and how to convert from one file type to another.

Supported Web mapping file types:
Below are a list of file types that I could upload to Carto, Mapbox, Google My Maps and ArcGIS online. There are probably more but this seemed like a good baseline. These are also all less code required sites.

• Zipped Shape files- Shape files are a multi-file format database and must be zipped for web use but this is supper easy, just select all of the needed files and zip. Shape files often have some constraints put on them in web applications so they are not always the best choice.  (Carto, ArcGIS Online)
• CSV -Comma separated values. First row must be names of each column and since it doesn't specify type most programs will guess. (Carto, MapBox, Google)
• Excel - No merged cells and no graphs or tables within the document (Carto, Google)
• Open Docs (Google)-  No merged cells and no graphs or tables within the document (Carto, Google)
• GPX - GPS exchange format. (Carto, Google, ArcGIS online)
• KML -  Keyhole Markup Language .  Keep in mind that though KML can store points lines and polygons in one file, for uploading into non Google formats you want to break it down in to one KML per feature type (aka one for points and one for lines)  (Carto, Google)
• KMZ- KML just zipped (Carto, Google)
• OSM -  Open street map dump (Google)
• GeoJSON- Java Script Object Notation, with geographic elements. Points, lines and polygons are supported but can't have more than one in a file for most uploads. Geometry collections type is not supported by Carto and will give an error.  (Carto, mapbox)
• JSON file name does not have the geo in front Carto seemed to do fine with these made from ArcMap but none of the other programs would work with them

 
After lots of looking there does not seem to be one universal file type with web mapping.  I didn't really expect there to be, but wanted to check. GeoJSON seem to be pretty popular in web mapping since its already in Java Script and many of the web mapping libraries are in Java Script. Unfortunately, in my experience GeoJSON files gave me the most trouble to create. ArcMap only converts to .json files which give me an error in Mapbox (and possibly others) that I can't figure out how to fix it.

So how do I get to the elusive GeoJSON....

Transforming one dataset into another - its magic! Without using code
Unfortunately this does not work with raster data you must first convert to a vector format for uploading.

Using Carto -
Ok, so you can upload lots of different file types into Carto and then download (click on the dataset, then export)  them as a .geojson or KML (also csv and shapefile). The only problem I found with this so far is that while your data is on Carto, unless you have a paid for account, the data is public. There doesn't seem to be a limit to how much data you can upload to Carto and you can delete it afterwards but if your data is sensitive this might not be the best plan.
 
Using QGIS -
Bring data into QGIS, right click on it and go to 'save as', then select geojson and make sure all parameters are appropriate and save where you want it. If you need to edit it convert after editing as QGIS cannot edit geojson.
 
These are the only non-code methods that I have been able to find that work for me.  Please share any methods you find or know of for file conversion!