This page is a preliminary page describing how we created the website, interactive maps, and panoramic photos; but also includes other technology used for the field work.
- Main Website Architecture
- Interactive Maps
- GPS Data Acquisition
- Temperature Sensors
- Panoramic Photographs
Main Website Architecture
2008: MapServer and OpenLayers
The interactive maps use a combination of technologies. For the 2008 field season, it quickly became apparent that both Google Maps and Virtual Earth simply did not have the required detail in the study area. Therefore we had to create our own maps. MapServer was chosen for this. This is an open source package that is very powerful and flexible, but it can be difficult to install. MapServer serves the Outline map, ASTER Satellite image, and Synthetic Stream data to the browser as a series of map tiles.
A second version of the map used a Microsoft Virtual Earth base map instead of the MapServer Outline base map. OpenLayers is very flexible and can easily incorporate a Virtual Earth layer. Virtual Earth adds better coverage of wider Costa Rica, but lacks detail in the study area.
The ASTER Satellite Image layer is a near infra-red daytime image taken by the ASTER imaging instrument flying on the NASA EOS Terra satellite. The image that we have used is taken from the ASTA Volcano Archive (AVA) for Arenal. These images are available via Smithsonian's Global Volcanism pages for Arenal. It was acquired on 29th August 2005, and has a Granule ID of SC:AST_L1A.003:2030725270.
The Synthetic Stream layer plots rivers, creeks, and streams that have been derived from DEM (digital elevation model) data. Ie. these are theoretical river positions based on height data. This works well for hilly areas, but it is poor for flat and low gradients areas. The data was calculated by the Inter-American Biodiversity Information Network (IABIN).
All of the blue map icons have been supplied by Sue Pichotta of Icons-Icons.com. All of these icons remain © Copyright 2008 Icons-Icons.com.
2009: Bing Maps and MapCruncher
For the 2009 field season, a new Bing Maps (nee Virtual Earth base map was developed that used map tiles created using Microsoft Research's MapCruncher application. This allowed us to overlay the ASTER imagery and a new high resolution aerial image on Bing Maps. This new map is no longer zoom-limited, and also supports bing Maps 3D. The tiles are hosted on Amazon S3 and served using Amazon CloudFront. Overlays continue to use KML. The synthetic stream data has been dropped.
2010: Google Maps and Multi-touch
The 2010 maps are very similar to the 2009 maps, but an experimemtal Google Maps v3 version of the map has been produced. The main advantage here is that Google Maps supports multi-touch interfaces (eg. as on an iPad). Bing Maps is only capable of this using Silverlight - which will probably never be supported by the iPad.
With an increasing number of year-specific icons and changes, the decision was also made to create new maps for each year. Currently there's the original 2008-9 map, and a new 2010 map.
GPS Data Acquisition
All of the groups are equipped with GPS devices for basic navigation. The mapping group are using a Trimble GeoXM handheld field computer with integrated GPS. They will be using this to acquire the boundary and grid base point; acquiring new map features; and accurately locating survey points for the other groups. The GeoXM is essentially a weatherproof Pocket PC with an extremely good GPS receiver and antenna. The GeoXM is capable of 6m accuracy. After post-processing (differential correction) this improves to 1m without obstructions. In contrast, a typical consumer GPS is accurate to about 16-30m. We are using Trimble GeoExplorer on the GeoXM. The laptop 'back at base' is running Trimble GPS Pathfinder Office for post-processing and data management.
The GeoXM was supplied by Cody Cantrell of Western Data Systems. Many thanks to Cody who spent a number of hours with us taking us through the Trimble software.
Onset Computer Corp's HOBO temperature sensors are used to measure water, air, and soil temperatures. These automated devices record temperature at periodic intervals. We typically use them for 24 or 48 hour intervals, but they are capable of recording data over weeks or months.
We intended to produce the panoramic photographs using RealViz Stitcher. RealViz were purchased by AutoDesk in early May, and the Stitcher product range is temporarily unavailable whilst the product line is re-branded. This unavailability has been expanded beyond the initial estimate from AutoDesk and we have been forced to use a different product. We have chosen the Canon PhotoStitch product for the 2008 field season. The advantages of this are that we have it already, it is simple to use, and it works. The features are relatively limited, so we may choose to use AutoDesk Stitcher in 2009.
Photographs are acquired using a Canon (EOS) Rebel XTi Digital SLR fitted with a Sigma 10-20mm wide angle lens set to 20mm. We shall also have a Canon 35-105mm lens for single shot photographs. The camera is mounted with the affordable Panosaurus panoramic head.
The Blog is implemented using Movable Type v4.1 (Personal). The style is modified from the standard Minimalist Green style.