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El mundo al instante

Geomatics Makes Smart Cities Reality

Enriching 3D Building Models with Non-spatial Data

e67fe3c2ccf76daf3890b1ea47fd4be32d6e21c0Today, the main use of 3D building models is for visualisation purposes. However, such models also have huge potential for supporting the ‘smart city’ concept. Disaster management, 3D cadastres, energy assessment, noise & pollution monitoring and visibility analysis could all benefit from enriched 3D building models. To demonstrate this potential, this article presents three case studies in which 3D building models have been enriched with non-spatial data. The datasets can be visualised and managed online within a web-GIS platform.

The technologies for capturing and processing 3D geodata are rapidly advancing. Aerial images processed with dense image matching algorithms result in automatically generated dense point clouds. Likewise, the data capture rate of Lidar sensors is still rising. As a result of these developments in geodata acquisition technology, the availability of 3D geodata is steadily increasing. Indeed, photogrammetry and Lidar together with 3D city modelling tools form the essential foundation for creating 3D textured building models.

Smart Cities

The current use of 3D building models is mainly confined to visualisation, which leaves many other potential applications underexploited. This is a pity, since urban managers and planners could benefit tremendously from 3D city models. This is especially true in light of the rapid urbanisation worldwide, which requires continuous monitoring of energy consumption, noise pollution and many other ‘smart city’ applications. Therefore, the major challenge for today’s geomatics professionals is to create affordable technologies that make optimal use of geodata and automated 3D city modelling tools. This includes the combination of these geomatics products – consisting of reconstructed 3D geometries – with non-spatial data such as building materials, number of floors and data captured by smart meters and noise sensors. Such efforts will result in a richer understanding of urban ecosystems and thus increase the liveability and safety in ever-expanding cities. More than half of the world population is already living in cities (an urbanisation milestone that was reached back in 2008) and it is envisaged that this share will be two-thirds by 2050, so there is a clear need for more efficient mapping, understanding and management of urban areas.

Bottlenecks

Airborne imagery has been and continues to be the main source for detailed 3D modelling of urban scenes. Nadir and oblique aerial images can be captured with high ground sampling distances (GSDs) providing highly detailed RGB and point cloud data. The main bottleneck in exploiting the full potential of 3D city models lies not in the availability of geodata, but rather in the lack of fully automatic and broadly applicable software tools. For example, commercial tools for processing aerial images do not enable the integration of the relative orientation parameters of multi-camera systems, which capture both nadir and oblique images, as constraints in the bundle adjustment. Furthermore, the matching of oblique and nadir images does not run smoothly. Added to this, during mapping, the available building primitives do not represent all possible architectural shapes, particularly in historical city centres, and façade point clouds are generally not considered during the fitting of primitives.

Non-spatial data

Enriching 3D city models with non-spatial information supports visibility analysis, urban planning, establishment and maintenance of 3D property cadastres, emergency response, estimation of the photovoltaic potential of roofs and energy demands, and other needs. These types of information are essential for city planners, policymakers, public administrations and many other users. The enrichment of 3D building models with additional information requires the realisation of a scalable system able to store, manipulate, analyse, manage and visualise different types of spatial and non-spatial data and their interrelationships.

Bergamo, Trento and Graz

From an algorithmic point of view, the production of 3D city models from dense point clouds can be classified into two main groups. The first group fits templates of specified roof shapes or building shapes to a point cloud. The second group simplifies 2.5D or 3D meshes derived from the point cloud until they meet ad-hoc geometric and semantic criteria. These two main groups have both been applied to aerial images of Bergamo (Italy), Trento (Italy) and Graz (Austria). Images of Bergamo and Trento were acquired by AVT/Terra Messflug GmbH Austria and of Graz by Vexcel. The size of the captured area is 5.3km by 5.6km for Bergamo, 3.5km by 1.5km for Trento and 3.0km by 1.5km for Graz. Table 1 provides further details about the three aerial surveys.

 

Bergamo

Trento

Graz

Area

5.3km x 5.6km

3.5km x 1.5km

3.0km x 1.5km

# nadir images

100

400

20

# oblique images

4300

-

160

Camera

UltraCam Osprey Prime

UltraCamXp

UltraCam Osprey Prime

f nadir [mm]

82

100

51

f oblique [mm]

123

-

80

GSD [cm]

12

10

12

along/across overlap

80/60%

80/60%

75/65%

       

Table 1, Details of the three aerial surveys; f: focal length of the camera, GSD: average nadir GSD in nadir images; all cameras are from the Vexcel stable.

The aerotriangulation (AT) was performed with ground control points (GCPs) and GNSS observations of camera centres, included in the bundle block adjustment process as observed unknowns. The AT accuracy reaches values below the mean GSD of the captured images. Dense point clouds were then produced using the nFrames SURE image matching software. After georeferencing, two distinct workflows were adopted to create the 3D building representations at the second level of detail (LOD2). Whereas LOD1 shows buildings as blocks with flat roofs, for example, LOD2 shows finer details such as roof shapes and protrusions in the façades. The Hexagon/tridicon suite of tools was applied to create the 3D building models, fitting roof primitives to the pre-segmented point cloud (hence the first group of 3D modelling approaches) for Trento and to the simplified 3D meshes for the Graz dataset. For the Bergamo dataset, both approaches were applied (Figure 2).

The reconstructed geometries of buildings have been enriched with energy-performance certificates, artificial night-time light locations and emissions, building property details and other non-spatial information. The building property details consist of, amongst other things, the owner’s name, the number of floors, the number of rooms and building surface materials.

Web-based Visualisation

The 3D building models and the linked non-spatial information are stored in two different data containers. Efficient managing of both data containers may be done through a service platform accessible from a web-based client. In collaboration with Trilogis Srl, the authors developed a dedicated web-GIS platform based on the NASA Web World Wind API to store, access, analyse and update the heterogeneous information linked to the 3D building models. The main potentialities of the approach include: (1) 3D navigation, data visualisation and rendering, including sources of artificial night-time light and thermal maps; and (2) data query and editing, displaying non-spatial data in pop-up windows where information can be edited, enriched and updated. An example for the city of Trento is shown in Figure 3.

Concluding remarks

3D geodata and geoinformation technologies will be key in supporting smart city concepts. 3D city modelling has attracted significant attention in recent years with numerous potential application fields, but there are many remaining challenges. One such challenge is that 3D buildings should represent more than just a realistic view of the urban environment, and an extension towards semantically enriched 3D city modelling is envisaged. Secondly, 3D modelling still lacks important automated components, and existing tools should be generalised towards the representation of different and more realistic urban scenes. Thirdly, the development of a common standardised data model is required, along with advances in hardware and software to manage massive datasets efficiently.

Acknowledgements

Thanks are due to project partners Trilogis (Italy), AVT/Terra Messflug GmbH (Austria), Municipality of Bergamo (Italy) and Municipality of Trento (Italy).

Further Reading

  • Biljecki, F., Stoter, J., Ledoux, H., Zlatanova, S., Çöltekin, A. (2015) Applications of 3D city models: State of the art review. ISPRS Intern. Journal of Geo-Information, Vol. 4(4), pp. 2842-2889.
  • Lafarge, F., Mallet, C. (2012) Creating large-scale city models from 3D-point clouds: a robust approach with hybrid representation. Journal of Computer Vision, Vol. 99(1), pp.69-85.
  • Remondino, F., Toschi, I., Gerke, M., Nex, F., Holland, D., McGill, A., Talaya Lopez, J., Magarinos A., (2016) Oblique aerial imagery from NMA – Some best practices. Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume 41(B4), pp. 639-645.
  • Toschi, I., Nocerino, E., Remondino, F., Revolti, A., Soria, G., Piffer, S. (2017) Geospatial data processing for 3D city model generation, management and visualizationISPRS Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., Vol. XLII-1-W1, pp. 527-534.
  • Toschi, I., Ramos, M.M., Nocerino, E., Menna, F., Remondino, F., Moe, K., Poli, D., Legat, K., Fassi, F. (2017) Oblique photogrammetry supporting 3D urban reconstruction of complex scenariosISPRS Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-1-W1, pp. 519-526. 

 

Last updated: 19/09/2017

http://Gim-international.com - Septiembre 19 del 2017

Implementing Land Administration Solutions in Ethiopia

Consultation with Stakeholders and Fit-for-purpose Thinking

9166e5a556c0cd1f41845376975cf1aef4eb46cdThe government of Ethiopia has demonstrated clear political will to advance the urban land rights agendas, but has struggled to sustain successful pilots. In a recent Technical Assistance project, a World Bank team including consultants from Land Equity International worked closely with the Ministry of Urban Development and Housing to evaluate the urban cadastral context. 

A recent Technical Assistance project to evaluate the urban cadastral context in Ethiopia closely mirrored the approach set out by the UN-Habitat and Global Land Tool Network publication called Fit-For-Purpose Land Administration – Guiding Principles for Country Implementation. Fundamentally, the fit-for-purpose land administration concept seeks to apply spatial, legal and institutional methodologies that meet the purpose of providing secure tenure for all, whilst recognising current political and institutional constraints. The fit-for-purpose mindset is one that actively focuses on purpose, seeks flexibility and plans for incremental improvement over time. As the authors’ second publication on fit-for-purpose land administration, this guiding principles document is not prescriptive, but provides seven steps – or categories – that provide a pathway to implementing fit-for-purpose land administration. These steps offer a framework for discussion of the project.  

Country context

The first step is analysis of the country context. Two schematics (see Figures 1 and 2) have been developed depicting the current status of the country context and spatial/legal/institutional frameworks of Ethiopia (solid red line), and the likely improvement that could be obtained with the preliminary interventions identified (dotted green line). Whilst these schematics could be improved for more universal application and could more closely mirror the fit-for-purpose framework, they do provide a summary and depiction of interventions likely to generate the greatest progress in a first iteration of activities.

Significant political willingness for land administration reform exists in Ethiopia. Past land reform and registration pilots have, however, largely failed. One reason for a lack of progress is the decentralisation of land administration functions: cities, rather than the national-level Ministry of Urban Development and Housing (MoUDH), are largely responsible for the actual implementation (and funding) of land regularisation and registration, making it difficult to fund, sustain and standardise efforts. A further complicating factor is the separation of rights-creation and registration activities, which are managed by separate institutions. And finally, there is no existing National Land Policy – although the Urban Land Development and Management Policy and Strategy forms a strong basis for such a document as well as potential to provide clarity around key aspects of the legal reform to support local implementation.

There is promise, however; whilst the rural and urban land sectors are separated in Ethiopia, the success in implementing fit-for-purpose principles of the rural registration projects to date provides lessons and impetus for the urban sector.

Frameworks

The second step is the analysis of existing spatial/legal/institutional frameworksIn contrast to typical discussions around fit-for-purpose land administration, the urban case of Ethiopia is less focused around the use of systematic registration, visual boundaries from imagery and participatory land adjudication. These practices have largely been adopted, with some level of standard piloting still required, and hence are not the main limiting factor. Instead, the core benefit of fit-for-purpose thinking lies in institutional reform with pragmatic decision-making relating to staffing, office setup and process standardisation.

Whilst there is presently significant overlap and conflict between institutional roles at sub-city through to national levels, pragmatically there is limited room for reform in the short term due to stakeholder pushback and the many historical causal factors. Greater rewards in terms of progress are likely to be seen in the computerisation of records, service provision interventions and implementation of a National Spatial Data Infrastructure (NSDI) policy. Some steps have already been taken towards these, with a land information system (the Cadastre and Real Property Registration System – CRPRS) currently being developed, but greater stakeholder engagement was highlighted as an immediate need to ensure alignment between this system and the existing legal and institutional structures.

The devolved nature of land governance and responsibilities can instead be addressed by the development of a set of standard operating procedures and clear project management. Weak project management to date was identified as perhaps the most significant limiting factor to immediate and sustained progress in reform.

Country-specific strategy

The third step is developing a country-specific fit-for-purpose strategy for land administration. There is a lack of an existing, comprehensive legal cadastre for urban land in Ethiopia, coupled with rapid urbanisation and high levels of informal housing. This particularly limits local government’s capacity to implement urban plans, enforce regulations and identify underutilised land that could contribute to alleviating the formal housing shortage. The lack of a comprehensive and accessible urban legal cadastre also hinders collateralised lending for development and equitable and efficient property tax assessment and collection that could contribute to municipal revenue and fund improved service delivery (see Figure 3). A country-specific fit-for-purpose strategy for land administration must hence address the above drivers, as well as align with existing urban policies and plans, such as Ethiopia’s second Growth and Transformation Plan.

As a result of the World Bank Technical Assistance work, a draft project design has now been developed in close cooperation with stakeholders. The overarching programme objective of the draft project design is to establish a legal cadastre to secure tenure for all in a system that focuses on good governance, the facilitation of investment and the operation of the real-estate market.

Designing country-specific frameworks

As a fourth step the country-specific fit-for-purpose spatial/legal/institutional frameworks are designed. Clearly the objective above is an ambitious one, the realisation of which would take a decade or more. A phased project approach was therefore designed, along fit-for-purpose principles, which built on the existing initiatives within government. The first project will develop and test the systems, processes and procedures, make the essential changes to the policy and legal frameworks and implement the legal cadastre in Addis Ababa and 23 major cities in the regions. The government already has in place the core components for this; what the project design adds is improved guidance on the project structure and management, capacity development, service provision and development of standardisation procedures.

The second and any subsequent projects will build on the results of the first project and extend the legal cadastre to all other urban centres throughout Ethiopia, ultimately achieving national coverage.

The following components were designed for the first project:

- strengthening and expanding the legal cadastre in Addis Ababa City Administration, including resolving the backlog, strengthening the involved Complaints Office and implementing an improved systematic adjudication and registration (SAR) process

- improving the capacity to implement SAR in the 23 cities, including strengthening the rights-creating institutions, undertaking file management (see Figure 4) and preparing a plan for regularisation

- strengthening the quality and services from the urban legal cadastre generally, including raising public awareness

- managing the project and establishing and implementing a monitoring and evaluation system.

Capacity development

Step number five is capacity development. As can be expected, substantial capacity development is needed to achieve the aims of the first project. However, the authors suggest that previously undertaken needs assessments have grossly overstated the human resource needs, particularly with the ambitious plans to digitise and computerise records and implement a sophisticated information and communications technology (ICT) system to provide efficient service delivery. Ethiopia continues to promote technical and vocational education and training in the land sector, which underpins future capacity. It is estimated that a maximum of just a thousand members of staff will be necessary to provide legal cadastre services in the 23 cities and Addis Ababa.

Country-specific manuals

Step number six is about country-specific instruction manuals. With project management being a core limiting factor, and with the potential for significant gains in the computerisation of the records (Figure 5) and service provision, the development of instruction manuals (including the standard operating procedures mentioned above) form a core part of the proposed first project. These should be accompanied by end-user training, the adoption of a service charter and clear mechanisms for monitoring (and, where possible, incentivising) efficiency. It is estimated that staffing can likely be halved if computerisation and standard procedures can be effectively implemented.

Economic benefit analysis

In the final step, the Costing and Financing of Land Administration Services (CoFLAS) tool –developed in conjunction with UN-Habitat and the Global Land Tool Network – has been used to estimate the potential annual operating costs and possible revenues based on staffing and resource estimates. It is suggested that the legal cadastre should be able to operate under a self-financing arrangement if fees for transfer are set at around 0.5-1% of the property value. Naturally this figure assumes that the costs of regularisation and first registration are separately covered, and it requires a strong and sustained public awareness campaign to ensure continued uptake of land services. Nevertheless, this shows a strong basis – and incentive – for implementing a fit-for-purpose approach to land administration.

Concluding remarks

There is a complex institutional environment for land administration in Ethiopia. Separate institutions and systems exist for urban and rural land administration, coinciding with a federal system where urban land services are provided at city level by regional governments under the oversight and guidance of federal authorities. Significant effort has been undertaken to develop the policy and legislative framework for urban land administration, but these initiatives have yet to evolve into efficient, cost-effective processes and systems that can be scaled up. Through close consultation with stakeholders and fit-for-purpose thinking, a strategy has been developed to address this.

Further reading

Fairlie, K., Burns, T., Zhang, Y., Adlington, G., Tamrat, I., Shibeshi, G., McDowell, A., Kebede, S., Zelul, A. (2017) Establishing a Legal Cadastre for Good Governance in Ethiopia: Identifying Bottlenecks and Steps Towards Scale-up, Conference Paper, Annual World Bank Land and Poverty Conference 2017, Washington D.C., USA

GLTN/UN-HABITAT (2015): Costing and Financing of Land Administration Services (CoFLAS) in Developing Countries. Nairobi. http://gltn.net/index.php/land-tools/gltn-land-tools/costing-and-financing-of-land-administration-services-coflas

GLTN/UN-HABITAT (2016) Fit-For-Purpose Land Administration – Guiding Principles for Country ImplementationUN-HABITAT/GLTN, Nairobi, Kenya. Available at: http://www.gltn.net/index.php/publications/publications/publications-list/download/2-gltn-documents/2332-fit-for-purpose-land-administration-guiding-principles-for-country-implementation

Last updated: 19/09/2017

http://GPSWORLD.com - Septiembre 19 del 2017

Arianespace to orbit 4 Galileo satellites in 2 launches

Arianespace will launch four new satellites for the Galileo constellation, using two Ariane 62 versions of the next-generation Ariane 6 rocket from the Guiana Space Center in French Guiana.

9 14 2017 Ariane6 pr

The Ariane 62 rocket. (Image: Arianespace)

The contract will be conducted by the European Space Agency (ESA) on behalf of the European Commission (DG Growth) and the European Union.

This is the first ESA first contract to use the company’s new rocket.

Stéphane Israël, Arianespace chief executive officer, and Paul Verhoef, director of Navigation at the European Space Agency (ESA), signed the launch contract for four new satellites to join the European satellite navigation system Galileo. The contract will be conducted by ESA on behalf of the European Commission (DG Growth).

These launches are planned between the end of 2020 and mid-2021, using two Ariane 62 launchers — the configuration of Europe’s new-generation launch vehicle that is best suited for the targeted orbit. The contract also provides for the possibility of using the Soyuz launch vehicle from the Guiana Space Center, if needed.

Both missions will carry a pair of Galileo spacecraft to continue the constellation deployment for Europe’s satellite-based navigation system. The satellites, each weighing approximately 750 kg, will be placed in medium earth orbit (MEO) at an altitude of 23,222 kilometers and be part of the Galileo satellite navigation constellation.

An ESA video about Ariane 6 is below:

Galileo is the first joint infrastructure financed by the European Union, which also will be the owner. The Galileo system incorporates innovative technologies developed in Europe for the greater benefit of citizens worldwide.

A total of 18 Galileo satellites already are in orbit. Fourteen of these satellites were launched two at a time by Soyuz launchers, with the last four orbited on a single Ariane 5 ES mission in November 2016. Two more Ariane 5 ES missions are planned on December 12, 2017 and in the summer of 2018.

Following the signing of this latest contract, Stéphane Israël, CEO of Arianespace, issued this statement:

“Arianespace is especially proud to have won this first launch contract for the Ariane 6 from its loyal customers and partners, the European Commission (DG Growth) and ESA. We are very pleased to have earned this expression of trust from the European Commission; by choosing to continue the deployment of the Galileo constellation with two Ariane 62 launches, they become the first confirmed customer for our next-generation heavy launcher, which is slated to make its initial flight in the summer of 2020. Through this decision, which adds two additional launches to follow the already-scheduled Ariane 5 ES flights, the European Commission and ESA are clearly indicating a key commitment to Arianespace’s next generation of launchers, which reaffirms more than ever its mission to ensure Europe’s autonomous access to space.”

http://GPSWORLD.com - Septiembre 19 del 2017

El lugar más caliente que haya existido jamás sobre la Tierra

Mistastinlakecrater kJbG 620x349abc

Hace 40 millones de años, un meteorito impactó en lo que ahora es Canadá, provocando la temperatura más alta jamás registrada en la superficie de la Tierra: unos infernales 2.370ºC. Esa es la conclusión de un equipo internacional de científicos tras analizar las rocas de un gigantesco cráter de 28 km localizado en Labrador. La pista se la han dado unas piedras utilizadas en joyería que compiten con los diamantes y que solo pueden formarse con un calor extremo.

Los investigadores saben desde hace tiempo que la Tierra fue bombardeada regularmente por meteoritos y otros objetos espaciales durante sus años de formación. Y algunas de esas colisiones dejaron cráteres que han sobrevivido hasta nuestros días. Uno de ellos es el del lago Mistastin, en Labrador, Canadá, cuyas grandes dimensiones sugieren que la roca que lo creó hace unos 40 millones de años era de un tamaño más que considerable.

La mayoría de los cráteres no revelan demasiado sobre el objeto que los causó, porque este se evapora durante el impacto. De igual forma, la mayor parte del material golpeado también desaparece. Por este motivo, a los científicos les ha resultado difícil aprender más sobre la naturaleza de las rocas espaciales y las condiciones que ocurrieron cuando golpearon la Tierra, explican en Phys.org. Una cosa que los científicos saben, sin embargo, es que cuando se producen estas colisiones colosales, una gran cantidad de energía se libera en forma de calor. Ahora, el equipo de Nicholas Timms, de la Universidad de Curtin, en Perth, Australia, ha sido capaz de medir el calor producido cuando el objeto golpeó el suelo en Canadá.

 

Según explican en la revista Earth and Planetary Science Letters, el equipo encontró evidencias de circonio, un mineral común, transformado en circonia cúbica, también llamada circonita o zirconita, una gema muy parecida al diamante. Resulta que hacen falta temperaturas de 2.370ºC para que esto ocurra, por lo que el calor generado por el impacto tuvo que ser ese por lo menos. Es la más alta jamás encontrada de forma natural en la superficie de la Tierra. Los científicos ya sospechaban que estos impactos podían alcanzar los 2.000ºC, pero había que probarlo. «Nadie había considerado utilizar circonio como registrador de las temperaturas de impacto», dice Timms a New Scientist. «Esta es la primera vez que tenemos una indicación de que rocas reales pueden ponerse tan calientes».

http://ABC.es - Septiembre 19 del 2017

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