Digital Geography

Python and Webmaps: folium

We have seen some easy ways to create webmaps without learning JavaScript or loosing sort of control of our data in terms of using a platform like cartoDB, mapbox or AGOL (ArcGis OnLine). There are R and QGIS connectors which translates your current data and project to a leaflet or openlayers based webmap. Today I worked with folium which creates a webmap directly from Python. Follow me!

GIS with javascript – tutorial part 1

An article from Anders. Geodata in javascript GeoJSON is the standard way of storing geodata in JSON, javascripts native data format. The wikipedia article has very clear and telling examples. If you have never heard of GeoJSON, read it. The aim of this article is to show you how to convert your geodata to GeoJSON and some basics in querying the data.

Non-standard use of Web GIS on the example of OpenWebGIS functionality

In this article we consider the use OpenWebGIS, as one of the free Web GISs for analyzing of buildings drawings, as well as mapping and measurement of small-scale objects that are demanded in archeology, architecture, biology, medicine and other fields of human activity. Tell me, how many online Web GISs can use the maximum zooming ratio of more than 19? Those Web GISs which use OpenStreetMap as a base map, generally have a maximum zoom to 19. Those Web GISs which use Google Maps as a base map, can increase to no more than 19-20, but in some cases this…

short announcement: learn to map with cartoDB

Dear folks, most of you probably know how to map things using software on your pc. Some of you might also know cartoDB. We like their service as our job-page here on digital-geography.com is based on their tables, API and GeoJSON export functionalities. Additionally it’s for free (with some limitations)… The guys from CartoDB now offer an online learning event which will give newbies the chance to map their data in a very interesting online mapping engine.

Online GeoJSON Editor

The web is built upon a small set of languages that are present everywhere. Besides HTML, Javascript is the most common technology around here.  So it is not a surprise that web cartography adapts this technology and uses the native javascript object type to store its vector data. The specification is called GeoJSON (for Javascript Object Notation) and extends the JSON model with geometry fields. But if you ever needed to write some lines of Javascript, you’ll know that it’s brackets can drive you crazy. So why would someone want to write table-like structures in such a quirky format? The…

how to create clustered points in leaflet

The leaflet API is very simple and tries to deliver best performance and style for commonly used features like tilelayers, points and lines and markers in general. So when we would like to visualize points it is possible to have a very large numbers of points. So lets have a look on such an basic example. I’ve created a point shape file with QGIS which has approx. 1.000 points embedded. Let’s have a look on a normal webmap with this density of information: As you can see, we’ve inlcuded a second js file with the point information called points_rand.js. You…

D3 Geodata Basics – A Map Overlay can have many Faces

Within that tutorial I will show you how to: add a geoJSON file using pure Leaflet open a geoJSON file with D3 open a TopoJSON file with D3 add a map-overlay to a leaflet map using D3 Again…we begin with a simple map … already seen in D3 mapping basics and in geoJSON & Leaflet Add a geoJSON file using pure Leaflet You should know how to do this! Just add some very simple data to the map, as we have already done it in a previous post! Import the data file… …add the data to the map… …define the…

cartoDB and Leaflet: creating the table or part one

We have already introduced cartoDB which is a platform for storing, administering and visualizing spatial data. One straight feature of cartoDB is the usage of GeoJSON for exporting their tables. In this tutorial I’ll document a working example on consuming this layer with leaflet. But first we will start with the easy part of creating the table in cartoDB.