From QGIS to Blender: Visualizing and Creating Georeferenced 3D models
For years GIS has been popular as a geo-spatial tool kit for scientists and researchers to map, organize, and analyze data[1]. Technical innovations have allowed people to push the boundaries of a GIS map, especially 3D modeling. This research is a proof of concept of integrating GIS and 3D modeling software — QGIS and Blender.
The research project will examine the possibilities of geospatial data manipulation and data visualization as a 3D model. The case study will be a systematic study of using pre-existing data of UNESCO World Heritage Sites (WHS) to plot, manipulate, organize, visualize and export a 3D model. There will be a creative allowance, in organizing and manipulation of data. It is a study to push the boundaries of a conventional 3D model, where the plotting of ‘point’ shapefile will be a key aspect in data visualization, by importing a WHS shapefile into Blender to create an exportable 3D model.
Background
QGIS is an open source professional GIS application available on Windows, MacOs, Linux and Unix operating systems. This software is a complete GIS system to manipulate spatial information to visualize, manage, edit, analyze, plot and compose as a map. QGIS is supported by a vast and continuously growing community of users and coders of python extension that are discovering and experimenting with new and creative ways to manipulate data.
Blender is a professional 3D creation suite, that is also open source, and available on Windows, and MacOs, and Linux systems. This software supports almost all 3D manipulation; modeling, rigging, animation, simulation, rendering, composing and motion tracking. This program is largely supported by creative experts in the field, who are constantly experimenting, improvising and improving Blender through regular add-ons and developments. The community is driven by peers who write codes for specific functions and expand the already existing functions.
QGIS and Blender, both are Python-based programs. Python is a high-level multi-purpose programming language which is easy to read, code and run. It is often the language most used for web-based application, especially for 2D and 3D imaging application[2].
The data set used to conduct this research was downloaded from UNESCO World heritage Center website. The World Heritage List is a collection of inscribed properties of Outstanding Universal Value according to the 1972 UNESCO convention concerning the ‘Protection of World Culture and Natural Heritage’[3]. There are 1092 inscribed properties to the list, that are divided into Natural, Cultural and Mixed categories; some sites are marked as World Heritage in Danger.
The World Heritage List is not just beautiful structures and natural wonders, it is a recognition of efforts of communities and countries, coming together to preserve irreplaceable heritage. The inscription of a WHS by UNESCO is of cultural, economic and political significance to any region. These sites are viewed as a commitment to preserve and safeguard heritage for future generations. Hence, there are many researchers and scholars who have studied the World Heritage List in detail, trying to understand its impact nationally and globally.
Methodology
This research will focus on two open-source software, QGIS and Blender, and their ability to represent data through 3D visualization, including an exported file of a 3D model format i.e a .obj, .stl or .dae. The aim is to explore creation of 3D models and visualization of map data through different fields in the attribute table of a QGIS file when imported into Blender.
There are many examples of compatible projects that have used geospatial data to create 3D models of cityscapes or terrain models using Digital Elevation Models[4]. It is necessary to have some form of data to use as elevation value to create a 3D, in aforementioned examples, the height of urban structures or elevation of terrain is used to input as a third dimensional value. However, Blender allows for any value to be used as an elevation value, especially in the case of an import from GIS file, any numerical value data can be used to arrange the shapefile vector to understand a different approach to data analysis in 3D.
The downloadable World Heritage list comprises different types of information about each site in both English and French. The fields of data include, unique number, ID number, name, short description, justification, date inscribed, date danger list, longitude, latitude, area hectares, cultural site criteria 1–6, Natural site criteria 7–10, State party’s name, and region.
The first step was to create a map in QGIS with the WHS data plotted on the world map. The base world map was downloaded from Natural Earth, which is a public domain with map datasets available at three different scales. The data sets include various classes of integrated vector and raster data. The base map is a country boundaries shapefile vector imported into QGIS.
The next step was to import and plot the WHS list into QGIS. This can be achieved in two ways, first by using the “spreadsheet layers” plugin in QGIS[5], or by converting the Microsoft Excel sheet of downloaded data from the WHC website into a comma separated values (.csv) file to be imported as a delimited text layer. The detail and all data fields can be viewed by opening the attributes table of the layer. The WHS for this project were then saved as separate layers as Cultural, Natural and Mixed, as well as divided into the five geographic regions (Africa, Arab States, Asia and the Pacific, Europe and the North America, and Latin America and the Caribbean) delineated by UNESCO.
These shapefiles were then imported into Blender using the GIS add-on developed by Domlysz. The download link comes with installation and operation details. However, the focus of the instructions was extracting a 3D model through a DEM, which caused several issues in this project. This addon allows for importing of shapefiles and georeferenced raster to be directly into the Blender software. The imported data can be assigned coordinate systems through the addon, for 3D models to be georeferenced. The data can be visually organized and treated through manipulation and application of different amplifiers. And eventually exported as a Wavefront object (.obj) file.
Results
Blender is a cross-platform program and should run equally on any operating system, it created several issues during this project on Windows that required several hours of troubleshooting. First of many issues was compatibility of QGIS versions with the Blender versions. Secondly was importing of shapefiles into Blender through the GIS addon. The polygon shapefile, which was the base country boundaries imported without any issues, however the point shapefiles were not able to be rendered or edited through Blender. These and some other minor issues had to be troubleshooted.
The results from GIS data manipulation in Blender is i) data visualization; to recognize different trends and patterns that may not be visible otherwise on a 2D plane, and ii) exporting of a 3D model to analyze and make the models easy to download and to be examined by fellow researchers. The polygon and point shapefiles when imported into Blender, did not behave by any similar means. The only way to make the point shapefile work was to convert the points into polygons in QGIS using the geoprocessing tools under the vector manipulation tab. The points were converted into polygons of fixed distance buffer option. Although there might be another way to achieve the desired result, this seemed the most effective.
The converted point shapefiles when imported into Blender were manipulated by assigning the Z value from the numeric fields from attributed data of the WHS data set. Assigning different Z values allows for the data to be arranged in varying ways, that allows for visual representation to be studied to recognize trends, patterns of geo-political implications of World Heritage Sites.
The shapefile world map and polygon were extruded using the solidify amplifier. The use of solidify amplifier allowed for the polygons to have a height, hence being translated as a 3D model. The solidified polygons were applied textures and colors for visual distinction and to be able to tell the layers apart from one another.
Discussion
The purpose of this project was to understand the steps involved in creating an exportable 3D model with georeferenced data. Although the latest QGIS version contains a 3D map viewer, it does not contain on option to export a 3D model. The representation and visualization of georeferenced data opens doors for many new opportunities for heritage managers, archaeologists, anthropologists etc. It is well known amongst the researchers that GIS has been the focal point of all types of research with a geospatial aspect. Therefore, researchers and data scientists are in constant search for applications, extensions and addons that will enhance this experience and analytical aspects of their studies.
There is a learning curve to Blender, since it is a professional software that has modifiable allowances through coding; it is not very user friendly. There is not a lot of scholarship about the GIS addon or the particular direction of this project, few online blog posts, where developers have shared their experiences. The lack of scholarship should not be considered a discouragement but an opportunity, that it is un-ventured territory, although there might other process out there to manipulate and visualize georeferenced 3D models, it was an interesting study that should be explored further and in detail.
Conclusion
This project is a study of two very important data manipulation and visualization applications, QGIS and Blender. These applications were selected because, both are free and open source application and coded through python programming language. QGIS and Blender having the Python language should technically allow for seamless importing and exporting of data from one application to other. However, since the addon is a part of a innovative and creative approach to geospatial and 3D modeling systems, it was bound to have some bugs and issues. Some of the issues discussed in the paper were resolved and some had to be worked around. The end product was a Wavefront object (.obj) uploaded to Sketchfab, however due to some rendering restraints the model was not properly visible. This anomaly was most probably because of the large file size.
References
· Morandi, S., Tremari, M., & Mandelli, A. (2017). Towards the enhancement of “minor” archaeological heritage. The International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, Xlii-2/w3(2), 503–509.
· Richards-Rissetto, H. (2017). What can GIS 3D mean for landscape archaeology? Journal of Archaeological Science, 84(C), 10–21.
· Sullivan, E. (2017). Seeking a Better View: Using 3D to Investigate Visibility in Historic Landscapes. Journal of Archaeological Method and Theory, 24(4), 1227–1255.
· Jiménez Fernández-Palacios, Morabito, & Remondino. (2017). Access to complex reality-based 3D models using virtual reality solutions. Journal of Cultural Heritage, 23, 40–48.
· Evangelidis, Papadopoulos, Papatheodorou, Mastorokostas, & Hilas. (2018). 3D geospatial visualizations: Animation and motion effects on spatial objects. Computers and Geosciences, 111, 200–212.
· Scianna, A. (2013). Building 3D GIS data models using open source software. Applied Geomatics, 5(2), 119–132.
· Domlysz. (2018). Blender GIS Retrieved from https://github.com/domlysz/BlenderGIS
· Blender foundation. (updated 2018). Retrieved from https://www.blender.org/about/
· QGIS. (2018, September). Retrieved from https://www.qgis.org/en/site/about/index.html
· Natural Earth data. (updated 2018). Retrieved from https://www.naturalearthdata.com/
· Python. (updated 2018). Retrieved from https://www.python.org/doc/essays/blurb/
· World Heritage Committee. (updated 2018). Retrieved from https://whc.unesco.org/en/list/
[1] Richards-Rissetto, Heather. 2017
[2] https://www.python.org/doc/essays/blurb/
[3] https://whc.unesco.org/en/list/
