Nov 032011

The blog content is licensed under the Creative Commons Attribution 3.0 Unported Licence.

IGIBS source code, i.e. the WMS Factory tool and the Mapping Application, is released under the modified BSD license. The full licence text will be included in any released source bundle.

The data licence(s) chosen depend on the original input data used. The WMS Factory tool will generate data (maps and tabular data) based on user-uploaded data which belong to their respective owners.

 Posted by at 15:20 Project Management, User Reqs Tagged with: , , , ,  Comments Off on Licensing for blog content, source code and data
Sep 162011

One of the main challenges in creating a WMS factory tool is to provide an intuitive way for end users to specify the rendering rules for the data they upload. Significant progress has already been made within IGIBS in calculating on-the-fly the minimum/maximum scale which is adequate for raster data. However, The cartographic rules mandatory for rendering vector data still needs to be manually specified by the user.

It is important to clarify that this is irrelevant to the SLD functionality for rendering custom vector data provided by OpenLayers. Loading all the vector data on the browser and letting the user change their style on-the-fly is not currently possible for the big datasets we are targeting. What we need is a javascript library that can query the features of a WMS and let the user specify styling rules for each feature based on certain criteria. This is unfortunately vendor dependent as a WMS GetFeatureInfo response is not standardised.

Possible approaches to specifying cartographic rules are to:

  1. Allow the user to upload an SLD file along with his/her datasets.
  2. Search for existing libraries that provide an SLD Editor functionality for a WMS.
  3. Implement a web-based WMS styling editor for a basic subset of the cartographic requirements that can be realistically implemented within a few weeks.

The first option assumes that a geographer using the service will have to write the SLD manually or use existing desktop GIS software that can export SLD files. This defeats the whole purpose of providing users with a tool to easily distribute their data as part of a fully functional WMS service and should only be used as a last resort.

The second option is an attractive one since web-based cartography is both important and missing. An independent project would mitigate the development to a central place, where different developers from different projects could contribute. Unfortunately there is no obvious existing tool that is feature-rich enough to provide the cartographic functionality of existing desktop software.

As a side note, there has been a promising initiative from OpenGeo to create a SLD editor that works with geoserver. A demo is available here. Unfortunately, after two years of development it does not appear mature enough and had no stable source code releases. Furthermore, it depends on openlayers and has therefore other shortcomings like the lack of support of multiple symbolizers per feature which is slated for the 2.12 release of OpenLayers.

The third option is the most reliable one for the short-term (i.e. next couple of weeks) and that’s the approach we are following. One can start with the basic rendering functionality using the most common styling rules: colour, width and transparency. Afterwards, a more extensive styling application can be developed to provide a long term solution to the problem of web-based cartography.

Please feel free to submit comments or suggestions bellow.


 Posted by at 18:37 Mapping Application, Techie, WMS Factory Tagged with: , , , ,  Comments Off on Web-based Cartography for the IGIBS WMS Factory tool
Jun 042011

One of the many goals of IGIBS is to generate Web Map Services that will be used in conjunction with INSPIRE type View Services which themselves are compliant with the INSPIRE Technical Guidance for View Services version 3.0. To that end, it made sense to take the following basic INSPIRE criteria into consideration when making our choice of tools:

  1. Support for the LANGUAGE request parameter in a GetCapabilities Request.
  2. Support for “extended attributes” including elements extending the
    _ExtendedCapabilities substitution group of the WMS 1.3.0 schema with a custom
  3. Support for the optional WMS 1.3.0 parameters wms:identifier, wms:AuthorityUrl and wms:LayerLimit

Up till ~3 weeks ago (May 12th) no stable release of either geoserver or mapserver satisfied any of the above criteria.

Mapserver Customisation

In order to make IGIBS services INSPIRE compliant we are using a customised version of mapserver 5.6.6. The customizations involve backporting selected features from the development tree of version 6.0 plus our own additions to add support for the LANGUAGE parameter and the extended attributes in the GetCapabilites response. The code is available for perusal here for any interested parties. It comprises a patch against mapserver 5.6.6 plus a sample mapscript wrapper that can be run as a cgi to provide an INSPIRE compliant View Service. Since Mapserver 6.0 the patch should no longer be necessary, but the mapscript wrapper is still required.

Latest Developments

On May 12, 2011 mapserver released version 6.0 and geoserver released version 2.1.0. As part of that release, Geoserver got funding from the Ordnance Survey to add support for the aforementioned INSPIRE spec as a plugin and can now satisfy all of the above criteria, while mapserver only got support for the wms:Layerlimit attribute.


The choice of software depends on one’s requirements. For a national mapping agency seeking INSPIRE compliance it seems that geoserver 2.1.0 is currently the best route. For the purpose of IGIBS, we will stick to the modified mapserver 5.6.6 for the following reasons:

  • Speed. Mapserver has performed considerably faster in our tests involving rendering and reprojection of geospatial data, which is crucial for the dynamically generated services of IGIBS.
  • Flexibility. Mapserver can be very easily scripted in a high level language for prototyping and experimentation.
  • Tried and trusted modifications to ensure compatibility while still being flexible enough to follow the fluid INSPIRE specs.
  • Geoserver does not yet fully support all parts of the INSPIRE TG e.g. the  “scenario 2” mentioned in the standard.

Please feel free to submit any comments.


Jun 032011

The overall aim of the IGIBS project is to try and improve the relationship between the UK’s National Spatial Data Infrastructure (SDI) as manifested through the UK Location Programme (UKLP) and the UK’s academic SDI.

Our main objective is to focus on use cases emerging from research and education related to a particular area – the UNESCO designated Dyfi Biosphere Reserve.  Once articulated, these user requirements will drive the creation of two pieces of software of wider applicability and assist Aberystwyth University in developing resources for use by local students.

We are building on much prior art, especially in the area of Access Control.  EDINA runs the UK Access Management Federation (UKAMF) and, while it might not be fashionable, the reality is that many SDI resources, eg, data and web services, are going to stay protected.  This is true both of INSPIRE at the European scale and the UKLP nationally.  We aim to show how Shibboleth (the open source software that underpins the UKAMF) can be used to enable a wider range of use cases, so that UK students can get access to both open and protected resources, eg, from UK public authorities like Welsh Government.

We expect that the main four products resulting from this project will be:

  1. Working prototype of a “WMS factory” tool
  2. Simple mapping application
  3. Best Practice model for using UK academic SDI at the departmental level
  4. Demonstration of UK access management technology being used to secure public sector services in combination with academic sector services

SDI is underpinned by open geospatial standards like the OGC’s Web Map Service (WMS).  The “WMS factory” tool will allow users to upload their data and instantiate a WMS so that their data can then be viewed online, via a simple mapping application, in conjunction with reference data from Welsh Government.

Shibboleth is already used in academia, we extend its use here to demonstrate how public sector data can be made securely available to authenticated and authorised users within academia.

The Institute of Geography and Earth Sciences (IGES) has ambitions to improve the way it educates students in the use of open geospatial interoperability standards and intends using the Dyfi Biosphere Reserve area as an exemplar.  To this end we are conducting an inventory of data for the area and creating a repository for educational use.  The “Best Practice model for using UK academic SDI at the departmental level” will feed into this activity as well as provide guidance for the wider university sector.

May 132011

Today I met with Jonathan Brownett an MSc student studying at IGES who is hoping to complete a thesis which will investigate land cover change over the Dyfi catchment area using remote sensing. He will use this method to determine the effects of land cover change on the hydrology of the area.

He would find this project very useful in compiling his thesis and already from the list we have compiled he has highlighted a number of data sets that he would like to have access to, to help him complete his thesis. So far there are at least 10 data sets that we have collated that will be useful to him.

After this I made a trip to Ynyslas where the Dyfi Reserve Manager Mike Bailey from CCW was able to locate a number of useful vegetation data sets initially taken from quadrats within the Cors Fochno bog area of the Dyfi Biosphere. This data will be of use to Professor Richard Lucas, academic from IGES and Alisdair Cuningham, PhD student who will be able to use this data for the BIOSOS project which they are working on.

I also received a list of IGES undergraduate proposed thesis titles and so far none of these are focusing on the Dyfi Biosphere. The Dyfi Biosphere is an area which could prove to be a huge resource to such students in terms of research already carried out in this area and the boundless possibilities it poses for more research. The proposed tool/mapping application could be used as a valuable tool for educating these students allowing them to discover the resources it holds.

May 092011

In the last couple of days I have met with a number of people who have previously or are currently working on projects within the Dyfi Biosphere. I have asked what data sets they have available and what their requirements of this tool would be.

I have met with Anthony Smith, the map curator in IGES. He agrees that the IGIBS data and tool would be very useful for both students and staff. The data acquired would also add to and help to update the map library. It also seems that many data sets relating to maps within the library are actually held among various researchers within the department. This currently makes it difficult for anyone to locate data sets relating to catalogued maps. The use of Geodoc for metadata recording and management might improve this situation but ultimately the Dyfi Biosphere and IGIBS mapping application would make all the information available in one site.

Alisdair Cunningham is a PhD student and is studying and developing methods for detecting habitat and land-use change in Wales using remote sensing. He will be concentrating his research on the Dyfi Biosphere area. He has many data sets available for the use of this project which have now been collated and stored safely along with other lists of data we are accumulating. Alisdair has said the proposed IGIBS tool and mapping application would be very useful for his research as it would draw together data sets compiled by other researchers. It could also act as a place to store his data sets so that they are easy to access, view, and compare. He would particularly like to use the LiDAR data from the Dyfi Biosphere.

In the process of collating the data sets for this project we have acquired LiDAR data of the area from a Dr. Angela Harris who is a lecturer at Manchester University and has been researching the use of remote sensing in monitoring northern peatland hydrology. She has also provided hyperspectral data and aerial photographs which will be very useful for Professor Richard Lucas who is working on a BIOSOS project in the Dyfi Bioshere and again for Alisdair Cunningham’s PhD research.

Already this project is linking people and their data sets with each other and should eventually prove to be a valuable and expanding resource to all researching and learning about the Dyfi Biosphere.

Apr 162011

IGIBS is going to try (I say try advisedly, as this is a project) to create a tool to allow the semi-automatic creation of an OGC Web Map Service (WMS). This will allow users to publish their data for viewing in a variety of WMS clients, one of which will be a demonstration mapping application we create. This page will have a technical focus and will be used to report bugs, progress, planning, etc. The idea is that as the project matures, this is where we collect information on:

  • Recommendations for what is necessary to take the “WMS factory” tool
    into production (if its doable)
  • Suggestions for enhancements to the relevant components of the UK
    academic SDI
  • Suggestions for next steps to take the mapping application forward
 Posted by at 15:35 Techie Tagged with: , , , , ,  Comments Off on Technical Category