Aug 28, 2009

How Does Remote Sensing and Airborne Digital Data Relate to GIS /CAD?

Estimated Article Reading Time: 4 min.

Satellite imagery and digital airborne derived geodata relate to geographic information systems (GIS) in many ways. Can you imagine collecting satellite imagery without having a GIS linked to it? It would be a rather pointless venture due to the fact that only pictures could be shown. Alternatively, a GIS would be considerably less effective and useful without satellite imagery. Imagery is a rich source of valuable information, and this data source is growing significantly.

Satellite imagery and airborne sensors collect information whose value far exceeds the value of finding your own backyard in a picture. Homeowner’s are not buying a whole lot of imagery, at least not in Berlin where I live, nor in Toronto where my mother is. Businesses and governments purchase imagery and aerial data products. They do so because they recognise these products have considerable value due to the information and knowledge that can be derived through processing them. This is a big deal – period.

Imagine a GIS without any satellite imagery or airborne data products available. There would be almost no way of covering large areas for major mapping and decision making projects and policy making, and even if data were aggregated for a number of places over time, that information would be old, far less useful and often riddled with errors because a standardized methodology for supporting it would not exist.

Do you think a NextMap Europe would exist? I doubt it. Most of those employee’s would be faced with the barbaric option of marching across Europe with surveying rods in hand, toting total stations, or maybe have the decades needed to collect the same data using GPS. There would be no Global Monitoring for Environment and Security (GMES) program, at least not with data supporting it. Baikonur Cosmodrome would be in economic dire straits and I suspect our colleagues at NASA would not have much use for this website. And, the new United States approval for an Imagery for the Nation Program would be out of business before even beginning.

Agriculture would be impacted greatly, forestry would be near impossible to do under the present circumstances and demands with this data and we would likely not even be talking about icebergs in the north or south because we could not see them.

Remote sensing data and airborne digital data are more essential today than yesterday and last year and the year before that. The information form these sources is now fully digital, available and presentable to almost any user around the world.

The growth in demand for this information has been, in many respects, due to the processing tools that support the raw data imagery. Definiens, ITT, ERDAS, IDRISI, GRASS and others are all producing software and imagery analysis products that extend the value of digital imagery information. Many of them incorporate GIS-like processing capabilities, bringing these functions directly into the image analysis workflow. Lines, points and polygons are more closely related to GIS than image mosaicing, handling multi-spectral and SAR related tasks.

A crossover of functionality has occurred in more recent times between GIS and aerial products. But there is more to this relationship than simple importing and exporting of data types and formats, as important as those functions are.

The greatest value of the GIS-remote sensing geodata coupling lies in extracting information from the imagery. That is normally achieved through GIS software, and often involves the integration of other pieces of information captured through different sources by different people.

It is difficult to think about managing an urban environment, especially one with a large area, if these tools do not exist. The element of time figures prominently into the management of city spaces where updated imagery on a regular basis provides a glimpse into these inner environments rapidly, efficiently and with a clarity not otherwise possible.

I am not aware of any tools that effectively present remote sensing information – outside of a GIS enabled environment. The logical flow of these information extends first to GIS then back out through cloud environments, web servers and digital documents. Note that cartographic production necessarily is involved in a workflow that originates and distributes remotely sensed geodata. Is there any point to raw imagery without presenting symbology, labelling, notation or geo-reference?

I think many people take imagery for granted, it is just there!

The relationship of remote sensing to GIS is tightly linked and not fully exploited. I often find that imagery and aerial products are purchased and held within departments, sections or branches of organisations, rather than being re-used, exploited and re-purposed. The administrative structures we tend to create for handling spatial ifnormation are old, outdated and unable to capitalise upon new products. About a month ago I listened in to a U.S. program online pertaining Congressional Hearings to the use of spatial information. Conclusion: more than once people pointed to organisational structure as a barrier to data use – even if they wanted to, they can’t. Make no mistake, similar circumstances exist in Europe.

The relationship of GIS and remotely sensed geoinformation is exceedingly important and holds great value. GIS and CAD tools are driving increases in exploiting that value through geoprocessing and analysis. People are becoming enlightened from what they are learning from these sources, but we need to ask ourselves, have we developed organisational structures to capitalise on these benefits fully?

We have much work to do on this front. Think about that relationship, it’s value and how you might conserve and nurture it in new and dynamic ways that fully exploit the tools and data.

Jeff Thurston is editor of V1 Magazine and V1 Energy Magazine for Europe, Middle East and Africa for Vector1 Media. This column rotates weekly

SOURCE Vector Media