Remote sensing analytical geospatial operations directly in the web browser

Masó J., Zabala A., Serral I., Pons X. (2018) Remote sensing analytical geospatial operations directly in the web browser. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives. 42: 475-482.
Link
Doi: 10.5194/isprs-archives-XLII-4-403-2018

Abstract:

Current map viewers that run on modern web browsers are mainly requesting images generated on the fly in the server side and transferred in pictorial format that they can display (PNG or JPEG). In OGC WMS standard this is done for the whole map view while in WMTS is done per tiles. The user cannot fine tune personalized visualization or data analysis in the client side. Remote sensing data is structured in bands that are visualize individually (manually adjusting contrast), create RGB combinations or present spectral indices. When these operations are not available in map browsers professional are forced to download hundreds of gigabytes of remote sensing imagery to take a good look at the data before deciding if it fits for a purpose. A possible solution is to create a web service that is able to perform these operations on the server side (https://www.sentinel-hub.com). This paper proposes that the server should communicate the data values to the client in a format that the client can directly process using two new additions in HTML5: canvas edition and array buffers. In the client side, the user can interact with a JavaScript interface changing symbolizations and doing some analytical operations without having to request any data again to the server. As a bonus, the user is able to perform queries to the data in a more dynamic way, applying spatial filters, creating histograms, generating animations of a time series or performing complex calculations among bands of the different loaded datasets. © Authors 2018.

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Communicating thematic data quality with web map services

Blower J.D., Masó J., Díaz D., Roberts C.J., Griffiths G.H., Lewis J.P., Yang X., Pons X. (2015) Communicating thematic data quality with web map services. ISPRS International Journal of Geo-Information. 4: 1965-1981.
Link
Doi: 10.3390/ijgi4041965

Abstract:

Geospatial information of many kinds, from topographic maps to scientific data, is increasingly being made available through web mapping services. These allow georeferenced map images to be served from data stores and displayed in websites and geographic information systems, where they can be integrated with other geographic information. The Open Geospatial Consortium's Web Map Service (WMS) standard has been widely adopted in diverse communities for sharing data in this way. However, current services typically provide little or no information about the quality or accuracy of the data they serve. In this paper we will describe the design and implementation of a new "quality-enabled" profile of WMS, which we call "WMS-Q". This describes how information about data quality can be transmitted to the user through WMS. Such information can exist at many levels, from entire datasets to individual measurements, and includes the many different ways in which data uncertainty can be expressed. We also describe proposed extensions to the Symbology Encoding specification, which include provision for visualizing uncertainty in raster data in a number of different ways, including contours, shading and bivariate colour maps. We shall also describe new open-source implementations of the new specifications, which include both clients and servers. © 2015 by the authors; licensee MDPI, Basel, Switzerland.

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Building the World Wide Hypermap (WWH) with a RESTful architecture

Maso J., Pons X., Zabala A. (2014) Building the World Wide Hypermap (WWH) with a RESTful architecture. International Journal of Digital Earth. 7: 175-193.
Link
Doi: 10.1080/17538947.2012.669414

Abstract:

The hypermap concept was introduced in 1992 as a way to hyperlink geospatial features to text, multimedia or other geospatial features. Since then, the concept has been used in several applications, although it has been found to have some limitations. On the other hand, Spatial Data Infrastructures (SDIs) adopt diverse and heterogeneous service oriented architectures (SOAs). They are developed by different standard bodies and are generally disconnected from mass market web solutions. This work expands the hypermap concept to overcome its limitations and harmonise it with geospatial resource oriented architecture (ROA), connecting it to the semantic web and generalising it to the World Wide Hypermap (WWH) as a tool for building a single 'Digital Earth'. Global identifiers, dynamic links, link purposes and resource management capabilities are introduced as a solution that orchestrates data, metadata and data access services in a homogeneous way. This is achieved by providing a set of rules using the current Internet paradigm formalised in the REpresentational State Transfer (REST) architecture and combining it with existing Open Geospatial Consortium (OGC) and International Organization for Standardization (ISO) standards. A reference implementation is also presented and the strategies needed to implement the WWH, which mainly consist in a set of additions to current Geographic Information System (GIS) products and a RESTful server that mediates between the Internet and the local GIS applications. © 2012 Taylor & Francis.

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Rubric-Q: Adding quality-related elements to the GEOSS clearinghouse datasets

Zabala A., Riverola A., Serral I., Diaz P., Lush V., Maso J., Pons X., Habermann T. (2013) Rubric-Q: Adding quality-related elements to the GEOSS clearinghouse datasets. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 6: 1676-1687.
Link
Doi: 10.1109/JSTARS.2013.2259580

Abstract:

Geospatial data have become a crucial input for the scientific community for understanding the environment and developing environmental management policies. The Global Earth Observation System of Systems (GEOSS) Clearinghouse is a catalogue and search engine that provides access to the Earth Observation metadata. However, metadata are often not easily understood by users, especially when presented in ISO XML encoding. Data quality included in the metadata is basic for users to select datasets suitable for them. This work aims to help users to understand the quality information held in metadata records and to provide the results to geospatial users in an understandable and comparable way. Thus, we have developed an enhanced tool (Rubric-Q) for visually assessing the metadata quality information and quantifying the degree of metadata population. Rubric-Q is an extension of a previous NOAA Rubric tool used as a metadata training and improvement instrument. The paper also presents a thorough assessment of the quality information by applying the Rubric-Q to all dataset metadata records available in the GEOSS Clearinghouse. The results reveal that just 8.7% of the datasets have some quality element described in the metadata, 63.4% have some lineage element documented, and merely 1.2% has some usage element described. © 2013 IEEE.

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Enhanced transmission of JPEG2000 imagery through JPIP proxy and user-navigation model

Monteagudo-Pereira J.L., Auli-Llinas F., Serra-Sagrista J., Zabala A., Maso J., Pons X. (2012) Enhanced transmission of JPEG2000 imagery through JPIP proxy and user-navigation model. Data Compression Conference Proceedings. : 22-31.
Link
Doi: 10.1109/DCC.2012.10

Abstract:

The efficient transmission of large resolution images is a key aspect in many applications to minimize the transmission costs and to enhance the browsing experience. Among the currently available standards for the coding and transmission of imagery, JPEG2000 excels for its superior coding performance and advanced capabilities. The JPEG2000 Interactive Protocol (JPIP) minimizes the amount of information transmitted in a client-server scenario. Nonetheless, JPIP does not provide mechanisms to re-use data already delivered to clients browsing the same image within a local network. Common HTTP proxy servers are not able to understand the syntax of JPIP, thus specialized JPIP proxy servers are put in practice. This work improves the capabilities of traditional JPIP proxy servers by means of a user-navigation model that, together with prefetching strategies, allows the server to anticipate (potential) future requests of clients. Experimental evidence indicates that the introduction of the navigational model into a JPIP proxy server enhances the browsing experience notably. © 2012 IEEE.

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Emerging data quality from GEOSS integrated clearinghouses

Serral I., Diaz P., Maso J., Pons X. (2012) Emerging data quality from GEOSS integrated clearinghouses. International Geoscience and Remote Sensing Symposium (IGARSS). : 2744-2747.
Link
Doi: 10.1109/IGARSS.2012.6350358

Abstract:

The GEOSS Common Infrastructure (GCI) provides a Clearinghouse (the GEOSS registry and metadata catalogue) and a GEOPortal to discover and visualize EO data in an integrated, standardized and interactive way, as well as broadly use it by the scientific community when dealing with representation and modeling of Earth Systems. EO data sources are ideally elaborated following quality assessment procedures, resulting in quality estimates and other related indicators. The objective of this indicators is to allow users deciding about data fitness for a purpose, but in practice systems providing methods to distribute, show and exploit this producer quality information in a standard and interoperable way are rarely used. This work aims to extract information about data quality from GCI metadata and analyze the obtained results. Additionally, an XML specific tool is able to quick and visually punctuating the metadata that refers to quality. © 2012 IEEE.

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