Posts Tagged ‘OSM’

A Quick Map With QGIS and OSM

Posted: June 18, 2015 in GIS
Tags: , , ,

What I love about QGIS is that one is able to create a nice map quickly. The other day I was asked to make a situation map for the project we are working on to include it into presentation. Аll I had was a laptop with no relevant spatial data at all, but with QGIS installed (I even had no mouse to draw something). Though it was more than enough: I loaded OSM as a base layer and used annotation tool to add more sense to it. Voilà:

Schema of the Conservation Areas in Leningradskaya Region

About a year ago I was asked to create a small (a B5 size) and simple schema of the conservation areas in Leningradskaya region. I did it using QGIS. Here you are the author version of the schema and several notes that might be helpful for a beginner map-maker.

There was a huge disproportion between areas of different objects and both polygon and point markers were needed to show them. I decided to use Centroid Fill option in polygon style to be able to use only one layer (polygon) instead of two (polygon and point). Using Centroid Fill makes points in centres of the small polygons overlap and mask these tiny polygons.

All the administrative borers were stored in one layer (and there are far more borders than one see here). They are drawn using rule-based symbology so I didn’t even need to subset this layer to get rid of the rest of the polygons in this layer.

All the names of the surrounding countries, regions, city and the water bodies are not labels derived from layers, but labels created inside the map composer. It was quicker and their position was more precise which is crucial for such a small schema.

There was a lack of space for the legend so I had to utilise every bit of canvas to place it. I had to use 3 legend items here. One of them is actually overlapping the other and setting a transparent background for the legends was helping with that.

Finally labels for the conservation areas (numbers) were outlined with white colour to be perfectly readable. Some of them were moved manually (with storing coordinates in special columns of the layer) to prevent overlapping with other labels and data.

P.S. Don’t be afraid to argue with the client about the workflow. Initially I was asked it manually digitise a 20 000 x 15 000 pixels raster map of the Leningrad region to extract the most precise borders of the conservation areas (and districts of the region). Of course I could do it and charge more money for the job, but what’s the point if some of that borders are not even to be seen at this small schema? So I convinced client to use data from OSM and saved myself a lot of time.

Donetsk Label at OpenStreetMap

Posted: August 31, 2014 in This and That

Now, when Donetsk became the hot spot of the civil war at the Ukraine I decided to take a glance at the map of the war zone. Of course I used OSM for this. But despite I knew the approximate location of the city I couldn’t find it for several minuets. I was confused… The reason was that “Donetsk” label (label of the city which is the administrative center of the Donetskaya region BTW) at the scales smaller than 10 km is suppressed by the label of adjusted town “Makeevka”. WTF?!

“Donetsk” (“Донецьк”) label at OSM is suppressed by the label of adjusted town

As you may already know, I’m a proud owner of AMD FX-8150 8-core CPU. And I’ve purchased it not for gaming reasons, but for science. My previous CPU was painfully slow with such calculations as determination of the relation between fires and distance to the nearest highway. I even didn’t try to perform that calculations to the whole dataset of the roads mapped in OSM in Leningrad region. But now I can do this!

With the new CPU I’ve recalculated previous distribution (with the same data) in dependence only on highways and performed new calculation on the whole roads dataset. Some numbers first:

  • 6,990 – number of fire points detected by FIRMS for the last 10 years in Leningrad region;
  • 10,966 – number of the highway features used as highways for calculations;
  • 87,422 -number of features from whole dataset of roads;
  • 2,3 Gb RAM and a single core were consumed by R during calculations for the whole dataset.


Recalculated fire distribution for the highways

Recalculated values for the highways are different to the acquired at the last time despite the data was the same. But there were hardware update and most important – software updates for R and its packages (OS was updated too). But this graph looks far more reasonable than the previous one.

Lets see what we’ve got for the whole roads dataset (I will compare it to the graph above).

Distribution calculated for the whole dataset of roads

The maximum distance from road decreased almost in to times: from 41 to 26 kilometres. The distance for the highest values decreased accordingly: a rapid decreasing stops at 7 kilometres and for only highways it was 18 kilometres.

So the first 5 kilometres from the road are the most probable zone fore the fire event. This distance is easily covered on foot in two hours. Another evidence of the massive anthropogenic impact on fire starting.

If I will ever lay hands on the road data from the topographic maps (here OSM data used) I will perform the calculation again to get the most precise data.

Conclusion: FX-8150 worth buying )))

There were 3 very interesting events on this week (during my official vacation):

  • a Russian – Finnish workshop dedicated to our project related to management of hazardous part of household waste.
  • An “International” conference named “An Environmental Equilibrium”; and…
  • OSM mapping party in Volhov town.

A workshop passed as always: Russians posed themselves as know-all persons (despite no one was prepared because all the materials were in English…), talked a lot but ineffective; and Finnish did the real job. For the first time in my life I had to be a parallel Russian-Finnish and a Finnish-Russian translator. A hard job, I have to admit…

 “An Environmental Equilibrium” conference (which first day I missed because of the workshop) exceeded my expectations… a little, actually, but nevertheless. The funniest thing was that the first face I saw when entered the lecture hall was the face of my scientific adviser, who new that I will participate but didn’t tell me that he will be a participant too O_o. He leaved quickly so we were unable to talk.

There were not as many people as expected (because of the summer time and a poor feedback from organisers, who didn’t provided participants with the time table in advance, I suppose the main part of scientists who sanded papers preferred to be somewhere else) – organisers even had to merge together all the sections because of the lack of speakers. The good thing was that the publications were ready and I was able to enjoy my article on the subject of illegal dumping monitoring at St. Petersburg with implementation of high-resolution satellite imagery. The bad thing was that my scientific adviser had already left the conference when I demonstrated my presentation.

 An unexpected finding was that the map in my Garmin, which expected to be fresh, had a poor an outdated information about location of the conference and OSM was also poor, but up to date.

OSM mapping party in Volhov was my first mapping party. Despite there were few  participants (actually if there were more of them I wouldn’t be able to participate at all because in that case party would took place a week earlier, when I was on vacation in Narva… and mapped it; collected data became more important due to imagery for Narva won’t be available soon) and heavy rain (from time to time) we were able to survey western part of town.

After 2 hours of mapping we gathered at the cafe to discuss our survey. I’ve made an attempt to find an answer for the the question about mapping managed green areas, but it seems that I’m the only one who care.

The most unpleasant part was an attention from drunken ex-prisoner in cafe, who started to ask questions about our activities and then begged for money for beer. In Narva my wife and I brought attention of the local drunkards while survey too…

In the end we had a nice attraction on board of Zverik’s jeep – a survey of the Russian roads 😉