You dataset might be too large for example, or you might need more flexibility. These are all useful tools, but in some cases they might not be enough for your requirements. I won’t go into that in detail here, but you can read up about it. One library that makes that very easy is turf.js. You should definitely preprocess your data, and remove geometries and properties that are not needed for your use case. Instead you have to play around with different algorithms and compare the results with the level of granularity and simplification you require. Unfortunately there’s not one simplification algorithm that gets it perfect every time. Sometimes, this kind of simplification will allow you to send a fairly complex map to the client in one go, so you don’t need a tile server at all. If you’re building a Node server, it also exists as an NPM package.Īll these tools have different ways of simplifying geometric shapes, which can be great for displaying large geographical datasets in the browser. Ogr2ogr is a CLI program for converting map file formats, importing data into geospatial databases, and much more. It’s easy to use, has a drag and drop interface, and lets you view shapefiles online. Mapshaper is kind of the opposite of QGIS, in terms of power vs. It’s very powerful and can do most things, but it’s a bit overwhelming. QGIS is an open source desktop application. Some handy tool for viewing and processing geospatial data: Usually I’ll convert it to TopoJSON or GeoJSON. It’s not JSON-based, and definitely not as web friendly. Shapefile is a very common data format as well. This is great for cutting down bytes on the wire, but it also means that it’s not as readable for us humans.Īnother slightly annoying fact is that most map libraries don’t support TopoJSON, which means that usually the server will send TopoJSON and the first thing you do on the client is to convert it to GeoJSON.ĭepending on the dataset you get large size savings though, so it’s definitely worthwhile. TopoJSON is also a JSON specification, which tries to tackle the file size problem of GeoJSON. There’s one big drawback of this format though - just like normal JSON, it’s a bit repetitive, so the file size can quickly become huge. As JSON, this is very web friendly, and you can represent everything from points to LineStrings to MultiPolygons.
Nodejs map how to#
GeoJSON is a specification for how to structure JSON for geospatial data. Great turnout at the ?? September Meetup! Learning about Building a Tile Server in by Jocke Bachstätter /tbxiOfQEoz- John-Paul Costales SeptemBackgroundīefore we jump in to building a tile server, an introduction to some general geospatial data formats and technology: Luckily, it’s not that hard to set up a tile server for yourself - I gave a talk about building tile servers at the Sydney Node.js meetup recently. There are online services that run tile servers as part of their offering (one example is Carto), but they’re not very flexible and none of them are cheap. If you can load tiles one by one, you don’t need to send the whole map to the client at once. These are tiles, and a tile server is the server that serves these images. You’ve probably seen an online map loading, and you’ll notice that it loads one square at a time. Technically at least, this is a solved problem. With one dot for every 16 million votes in Australia, that’s a lot of JSON data! We had a similar problem with a smaller but similarly data-heavy project, our Every Vote map that was published in the Guardian. The JSON payloads would just be too huge. Essentially, this project was too large to render whole maps at once on the client side.
![nodejs map nodejs map](http://www.learntocodefromhome.com/app/images/nodejs-logo-4.png)
Unfortunately it’s not a public project, but if you’re curious, you can check out our projects page and read about it.
![nodejs map nodejs map](https://i.stack.imgur.com/dYvYp.png)
It was a huge dashboard with over 10 different maps, each based on a large dataset that needs to be updated from a data management system. Recently, I got the chance to work on a backbone application where I understood the primary importance of selectively using javascript built-in objects for our operations regardless of the framework.Lately I’ve been working on a big project for Transport for Victoria. Most of the times we pledge our allegiance to our lords (frameworks) and libraries and follow them blindly because we think that they are capable of doing everything, sometimes losing out on javascript best practices. (Oh! The Internet is the deep blue sea I was talking about).Īs frontend developers most of the times we do not rely on vanilla javascript for everything that we want. Although most of us do not venture all the way down into the darkness, we still precisely like to get what we want. You are on a boat in the middle of a deep blue sea. The internet is a great place to find information, but there is one teeny-tiny problem.