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Wednesday, 27 May 2015

QGIS Sample Atlas

Recently, I have been pushing myself to test my capability in generating high quality cartographic works in QGIS. Since I took on a mini project on Malaysian state of Kedah, this atlas was truly a combination of open source data and open source software.

For data in Malaysia, I manage to obtain through third party sources for district, subdistrict and voting locality boundaries. In Malaysia, these sorts of data are super hard to find (generally all forms of datasets for large scale maps of Malaysia are not for free). The roads, railways, rivers and land use data was sourced from Open Street Map (I recommend http://extract.bbbike.org/). Avoid choosing QGIS tool for Open Street Map as you get good coverage of the dataset with minimal attributes (making them redundant). The terrain is not exactly open source as it came from ASTER GDEM and hence, it restricts anyone to produce commercial maps.

The software I used was QGIS. In order to produce 200+ page atlas (based on sub district levels), I used Print Composer. It is the equivalent of Data Driven Pages in ArcGIS. I have made full use multi map concept where I can pinpoint the reader where they are (the inset maps). The legend size remains difficult thing to adjust (now I realized there is legend customization through filter) as it dominates a significant chunk of the map. The scale is tricky part and I resorted to numeric figure as QGIS hasn't improved on the variable scale legend. Now, I also realized there are better options to choose from for the North Arrows.

How about the map itself? I used pretty much standard colour schemes for every dataset for the atlas. Hillshading worked out very well  for the Bandar Padang Mat Sirat and Bandar Yan (impressed with QGIS capability). Choosing the colour of roads required much judgment as the terrain colouring exerted its influence significantly. The text visibility has been controlled after much playing around and deliberation. The original dataset of roads showed many road segmentation, Using the blending option, I was able to show a full continuity for the highways.A lot of judgement was used to determine how many layers are relevant to the atlas and which ones need to be kicked out.

Below here are some examples of urban, semi-urban and rural settings of Kedah (viewed through maps). When the final product came out, I was impressed with QGIS capability. For more maps, please contact me here.






Sunday, 24 May 2015

DMS QGIS Forum

Speaker from Responsible Gambling Foundation (Victoria) on how QGIS is applied
for assessing the proximity of pokies (gambling areas) and gamble help centres
On 14th May 2015, in the beautiful Crown Towers site, Digital Mapping Solutions (DMS) hosted a well-attended QGIS Forum. They brought city councils, companies and freelance cartographers together to listen about the progress in QGIS and its application in real scenarios. DMS is the forefront in advocating QGIS to many of its clients, active participant in QGIS development and conduct many training of QGIS. For those who don't know, QGIS (formerly Quantum GIS) is an open source GIS and increasingly adopted globally.

Despite being hosted in expensive Crown Towers (next to the Casino), DMS surprisingly hosted the morning session about QGIS with sumptuous breakfast for FREE! They are generous indeed especially the heavy breakfast! For this discussion, I will point out specific things you need to know about QGIS (which was discussed in the forum).

  1. How can I submit an issue or feature request for QGIS? Proceed to the website here
  2. How can I retain the layer file in QGIS? The .qlr file is the equivalent of ArcGIS layer file . Refer here
  3. Group layers in QGIS. Refer to this YouTube link
  4. You can import a CSV file containing a particular font setting which allows QGIS to customize the labeling based on the imported CSV.
  5. How can I produce a map where the main focus stands out as a figure? Use Mask and watch this YouTube link :                                   
  6. In the print composer, you can add the raster image as background and use blending tool to adjust the visibility strength of raster image
  7. How can I customize a legend that is only relevant to the map content? I would like to have the legend to show the layers visible on the map. Use the filter (in Legend). Refer here (Go to Legend Items)
  8. Presets can control the number of map layers viewable and it is useful for the multimap concept in print composer. Refer here
  9. QGIS is not just for desktop maps, it is also for publishing web based maps. Use qgis2leaf and read here for more details.
  10. In the forum, we have seen the demonstration of city councils of utilizing custom forms in QGIS. Refer here on how to create QGIS custom forms
From the presentations, I have noted city council organizations have been slowly dropping off the commercial GIS software in favour of QGIS. This is because the councils would like to lower the software maintenance cost and cheaper GIS distribution within the organizations, However, before embarking such transitions, each organization must undergo fundamental training in QGIS. 

I hope you find the 10 tips above allow you to explore more in depth the power of QGIS in various aspects.