Wenn Sie wissen möchten, welche Technologie Google und Yahoo Maps so schnell macht…
Rich Map Format (RMF) is a proprietary and patented data format of Telcontar.
It is a highly compact, binary format optimized for spatial query processing and lies at the heart of Telcontar technology. In fact, some of Telcontar&apo;s advantages derive directly from exclusive utilization of RMF.
RMF is partly a compaction (not compression) scheme. RMF squeezes out some of the „white noise“ present in other data formats by a clever and efficient encoding of the data. Fixed-width fields clearly demonstrate the concept of „white noise“. A fixed-width field of 25 characters is always 25 characters long regardless of whether any information is present. In the RMF, only useable information makes it in; „white noise“ disappears.
RMF further reduces the file size by eliminating redundancies that appear in the data. Many formats contain megabytes of redundant information. For example, a stretch of road may have the same name for nine segments. Instead of assigning the same name to each of those nine segments, RMF assigns the name once for a designated begin location and an end location.
Traditional formats include the name attribute of „Main St“ on all nine line segments as illustrated in Figure 1. However, in RMF, „Main St“ is set down once and the other eight line segments refer to the first one for the name attribute.
Finally, RMF shrinks the file size one more time by converting the data into a binary format. All of this compaction results in an amazingly small file size. An RMF file typically ranges from 1/10th to 1/15th the original file size. For example, a 100GB GDF file ends up as a 5GB to 10GB RMF file.
Another key advantage of RMF is that it is spatially organized. A spatial format organizes data in a multi-dimension fashion such that features near each other in reality get stored close together in the database.
In a sequential file sorted by name, address, or street name, these points of interest (POI) would be located at opposite ends of the data set with thousands, or even hundreds of thousands, of records in between. In a spatially organized format, the items are located adjacent to each other, just like they are in reality. This means that once you find a location in a spatially formatted dataset, you can quickly find other close by POIs, addresses, features, etc.
Map vendor independence is a key value proposition of Telcontar&apo;s products. RMF allows you the convenience of including multiple datasets in a single format. A single format means your application is written once but may utilize a variety of map data sources. For example, one dataset may be used for routing and another for display. If you are unhappy with one dataset, you can easily swap it out for another one.