Tag Archives: gis

SLD in HTML and SVG

sld

A standard way to style any OGC layer is using SLD. Styled Layer Descriptors.

The Styled Layer Descriptors are a simple (and standard) way to style your web maps. But when you style you also want to generate a nice legend for it.

I recently found myself with the situation of reworking a website styling code. Instead of writing it from scratch we used existing pieces to cleanly fill our webapp divs with the correct legend.

Let’s style!

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Filed under code, gis, Maps

KML to DXF (hell)

kmlhell

The time goes by and I don’t have enough personal space to write in this blog. It is crazy how life changes and how many things are thrown at you.

That being said, recently I helped a friend with some format problems, and I thought it was a perfect excuse to prepare a new blog post.

come get some

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Filed under gis, ogc, tools

Getting information from IPs

earth

Posts come very slowly, but here’s another one.

This post won’t be useful for most people :-(. You know when you use google analytics and get that fantastic map showing where people connect from? Read this, and you will learn how to do it yourself.

Tell me how

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Filed under code, curious, gis, Maps

Color to attribute. Qgis 2.X

qgis-logo-plugincolor

In 2012 I created a small plugin for Qgis1.x. It allowed you to modify a vector layer, creating a new column to hold the color of the features. This proved useful for me at the time. I could use Qgis to decide the color palettes and then export to wherever I wanted.

Come 2013, a new version of Qgis appeared, and the plugin broke. I wasn’t using it at the time and I didn’t realize it. But someone did, and kindly pointed me to the problem. I don’t have as much free time as I used to. However as my grandma used to say “better later than never”, here we have the plugin to work with the 2.x series!.

You can get it from my github. The master branch has the original code, and there is a new qgis2.0 branch with the new revamped plugin.

Salut!

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Filed under gis

Convex Hull, one algorithm implementation

chull
I talked about convex hulls some time ago in an alpha shape post.

The convex hull is probably one of the most basic computational geometry algorithms, and because of that it is present in almost, if not all, geometry/cad/gis libraries and software packages. In this post you will find an explanation of one of the existing algorithms to compute it, an implementation with C++, plus a set of scripts to generate various point clouds and the corresponding hulls.

Objective

  • Describe one of the possible convex hull algorithms
  • Implement the algorithm in C++
  • Provide various scripts to generate random point clouds and compute its convex hulls

I won’t lie to you, this post might be boooring ;-).

continue to this long post

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Filed under code, gis

Basic Network Analysis With GRASS

I performed a little network analysis with ArcGIS on the Schools in Enschede. Given a shapefile with roads and the school points I obtained the service areas at 1km and 2km from the schools. Can I obtain the same with GRASS?

Brilliant! I want to read more

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Filed under gis