Coordinate precision In MapInfo
Pete Smyth
MapInfo stores all coordinates internally as long integers ranging from -1 billion to +1 billion. These internal coordinates are translated into "coordinate system" coordinates by applying two linear transformations - - one for the X coordinate and another for the Y. The coefficients of these linear transformations are determined from the bounds of the coordinate system.
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Uffe Kousgaard
andre boessenkool
Forum,
I am looking for some advice:
I have a number of ESRI shape files, each containing several data classes. For example a ROADS file would contain freeways, national roads, main roads, minor roads, secondary roads, 4x4 tracks, streets etc. Similarly there are other files containing several classes of data. This stuff is all to be mapped, each class with its own style parameters (e.g. a freeway in a thick blue double line, a secondary road in a narrow yellow line etc.), all with the appropriate colors, labeling etc. etc.
Now, as we go, new shape files will replace the older ones, as more information becomes available. The idea is that I would like to be able to just replace the old shape files for new ones, import them in MapInfo (replacing the TAB files) and simply let the mapping software operate on them to generate a new map product. Typically this will be on a once a year basis.
Until now I have used MapInfo for a number of years and in order to achieve the type of map required, the shape files were split into as many TAB files as there were classes of data in each of them (I had freeways.TAB, mainroads.TAB, well, you get the gist). In a repetitive scenario like described above, I will have to do this split up every time a new, updated shape file becomes available. My question is: is, what I did until now, necessary or can this somehow be avoided, either within MapInfo, or perhaps by using different software. I must admit, at this stage I still work with MI v. 4.5. Lately I have been looking into MAPublisher, but I am not sure that it can do what I am looking for.
In anticipation,
andre boessenkool
Skype: aboes2000
Lat: S 33.940
Lon: E 18.766
Tim Rideout
Andre,
There is no real need to split your shape files into multiple layers, either in MapInfo or MAPublisher within Illustrator. TAB files support different symbolisation for every object so queries such as Select Freeways, Apply Freeway Style (this isn’t the real syntax), Select A Roads, Apply A Road Style, are all that is needed. This could be set up as an MBX that you ran each time.
In MAPublisher you would just create a stylesheet based on the feature codes. After import of your new shape file you would drag it into the correct style sheet and it would pick up the correct styles.
Hope this helps
Tim
Dr Tim Rideout
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andre boessenkool
Thank you, Martin and Tim,
The shape files do contain fields specifying the type (or ‘class’) of data. I’ll look at the thematic solution and also at the MAPublisher solution.
andre boessenkool
Skype: aboes2000
Lat: S 33.940
Lon: E 18.766
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