The pain points for managing geospatial data are the same, regardless of application area or the tools that are used. There are a number of problems that geospatial practitioners encounter when managing their geospatial data, from finding their own data to distributing their final work to others. Having a geospatial data management strategy enables high performance use of spatial data, ensuring efficient data discovery, acquisition, processing, analysis and modeling, and data delivery.
The Uniqueness of Spatial Data
As we’ve built upon our understanding of the Earth’s shape over time, there have been different geographic coordinate systems employed to mathematically define the shape of our planet. The study of the Earth’s shape is called geodesy, and the mathematics of these measurements can get quite complex. The problem is analagous to peeling an orange then attempting to lay the peel flat, mapping the round Earth to a flat map requires corrections.
Known as geographic coordinates, latitude and longitude vary by distance across the Earth’s surface. One degree of longitude and one degree of latitude are different distances for different places on the planet. Grid coordinates are an alternate way of looking at Earth measurement, with an attempt to divide the Earth into regularly shaped grid squares. There are also a number of different map projections that abstract our 3D world for 2D display.
The different models of the Earth are known as datums, and integrating data created in different datums is a challenging problem as each piece of data needs to be aligned and transformed to each other in order to preserve the correct position on the Earth’s surface. Users are focused on quickly generating results and using the data to generate custom products, they rely on data translation tools to help solve these complex data transformations.
The various different measurements and projections are of particular importance to international data providers, that distribute remotely sensed imagery collected for all places around the world, by different providers and from different sensor types. Solving integration issues is facilitated by allowing data to be transformed into various datums and projections.
Avoiding Duplicate Efforts
When compiling data for a specific project, it’s not uncommon to realize that the data were collected some time ago, before significant changes took place on the landscape. In larger organizations, there may be another employee or department that has already acquired more up-to-date data, but current users may not be aware of it. This lack of a central management tool can lead to duplication in cost and effort. Companies with poor data storage and retrieval infrastructure never fully realize the value of the investment that was made to acquire the data in the first place, because it may get filed in some desk drawer where only a few people know where it can be found.
Poor data storage has a cascading effect, because storing the same data twice (or in some cases four, five or six times) eats up a lot of storage space. Duplicity also causes needless expense due to the time and energy spent maintaining and compiling the right information.
In many cases the deliverable at the end of a project is still a paper map that must be output and sent along with supporting data and with methodologies explained in report format. When organizing geospatial data for internal and external customers at the end point of a project, a lot of time can be spent copying and formatting the data. Data distribution in digital formats, such as DVDs or CDs is often still a manual and time-consuming process that gets done on individual workstations, taking worker time and valuable computing power away from other tasks.
Streamline the packaging and delivery of data is important to efficiency. Today’s Internet publishing frameworks allow for the streaming of geospatial information. Streaming standards created by the Open Geospatial Consortium allow for Web Map Service (WMS) or Web Feature Service (WFS) distribution. Users that author map documents can also author a streaming map, where text and vector layers on the map can be provided to other subscribed users. The author has control over who accesses the map service, and can distribute it.
In many organizations there are sensitive data sets that can only be used by specific people, and that can’t be exposed to the outside world. Given these restraints, a geospatial content solution must employ security and job-based access rules in order to ensure that operations aren’t compromised, and that those that are authorized to use specific data have quick and easy access to it.
Content management allows you to put different data sets into different use pools, and provide different access to different people. Access to different data that are authenticated also has the advantage of allowing you to audit use in order to understand how, when and how much your data are used.