The 3-rd Annual International Conference: Space Survey at the Height of High Technology organized by the “Sovzond” Company took place on April 15-17, 2009 in a near-Moscow town. The Conference (click to open the program) becomes more and more popular and has justly turned into one of the most significant events in our GIS-community providing an opportunity to sum up the year and discuss challenges and outlooks of the Earth remote probing.
This year, the Easy Trace Group represented the report "...Digital substrate for photos. At a low price...".
Theses of this report are given below:
Search of ready digital substrate often brings nothing. For many reasons. The substrate you need is missing and never existed. Or it is available in a wrong format and with a wrong classifier. Available, but inaccurate and incomplete. Or secret. Or too expensive…
On the other hand, you already have paper maps or they are within easy reach. But the price of their transfer into digital form is high or you may not order it for security reasons.
Let us consider the price of map digitization. It is high indeed, mainly because the tools commonly used for this purpose are not designed for it. This state of things is caused by several reasons.
First, such worldwide brands as ESRI, MapInfo, Autodesk, Intergraph, etc. DO NOT PRODUCE specialized tools for digitization (not photo decoding but just vectorizing of paper maps).
Second, the enterprises duty-bound to “fill the digital void” are forcedly equipped with the Panorama package. It means, they use a tool totally unfit for effective digitization.Third, the propensity to use cheap non-license copies of expensive software still exists, even if the products are NOT DESIGNED for vectorizing. At that, high price of originals creates an illusion of the best possible technology.
And that is almost true. Actually all digitization projects are transferred from developed countries to India. And none of the brands will ever create a tool for the country where it will be rather cracked than bought.Anyway, Russian companies hardly can order cheap digitization in India. Because of secrecy, if nothing else.
So, is it possible to make digitization less expensive in Russia? Yes, for sure.
The way out is the use of specialized map digitizing solutions. These packages dramatically change the notion of vectorizing cost and duration, even for data-saturated color topographic maps.
Don’t forget, we are discussing processing of Russian maps – poorly printed and badly threadbare.
Fundamental reduction of processing time is possible only under the condition of automatic digitization.At that, classical methods are not suitable for vectorizing of badly damaged color materials. It is simply impossible to create a formal set of parameters that would unambiguously classify both the image and the resulting consistent vector model.
The only possible approach is “divide and conquer” - an ancient but still relevant motto. Yes, automatic vectorizing of a color image is unfeasible still, but individual thematic layers of the image fit for such processing well.With some simplifications, the scheme of digization is as follows:
- extraction of a thematic layer;
- automatic tracing, data recognition, classification, correction, coordination and control of automatically detected vector objects;
- extraction of the next raster layer assisted by already digitized vector data, its digitization;
- …;
- final coordination and control of the complete vector model of data.
At that, all operations of vector data correction, coordination, optimization and control are run in the automatic mode.
Some manual labor should be done of course. But it concerns macro-correction of common boundaries and junction points of vector objects rather than editing of individual vertices.
To sum up, the following arguments are “pro” the use of specialized digitizing software:- use of unique specialized utilities and tools;
- digitization in the form of a production line in one shell;
- automatization of labour-intensive operations, both at tracing and manual correction;
- low cost of a working place for vectorizing.
As a result, use of a vectorizer greatly decreases time and cost required for map digitization or, to put it more precisely, for forming of a complex and correct digital data model with attributive information.
The above-mentioned approach to digitization is considered by the example of Easy Trace PRO version 8.6.
P.S. Digitization of maps will be of current importance until we use paper…