Electricity, telephone, district heating, gas, optical fibre, water … All these networks intertwine, rub shoulders, overlap and some have been there for so long that even the memory is lost and their managers know more about the exact location.<\/em> To open a trench on the public road becomes more and more risky.<\/em> So much so that after very serious accidents, the MEEDTL decided a very large reform.<\/em> A one-stop shop will list all the network managers, contacts and eventually the areas of implementation.<\/em> It will be consulted for the declarations of project of work (DT) and the declarations of intention of beginning of work (Dict).<\/em>
In the process, the regulation of these declarations is recast.<\/em> <\/p>\n\n\n\n
All new network work will be georeferenced and subject to three accuracy classes.<\/em><\/strong> All the operators of the various networks are required, by January 2019\nto respect the obligation of basemap and georeferenced routes for the sensitive\nnetworks buried in urban units. For networks outside urban areas, the deadline\nis January 1, 2026. <\/p>\n\n\n\n The job seems simple at first glance. Three classes have been defined: <\/p>\n\n\n\n Class A<\/strong> [\/ stextbox] <\/p>\n\n\n\n Let’s leave aside, for a moment, the technical aspects of measuring\nuncertainty and move on to the first major problem of this project. It all\nboils down to the phrase \u00a0\u00bb if the maximum uncertainty of location\nindicated by its operator is higher …<\/em><\/strong> \u00ab\u00a0. <\/p>\n\n\n\n Definition of LOCATION.<\/strong> <\/p>\n\n\n\n Everyone understands this sentence without having to think about it. If\nI have a gas pipe under the sidewalk, parallel to the edge of it, I can\nclassify this pipe in class A if its position is known with less than 40 cm of\nuncertainty. In front of me the sidewalk is 70cm wide, so necessarily the\ndriving will be class A. It would be so simple, only if it was true! <\/p>\n\n\n\n First thing that should put us in the ear: why in the previous example\nask 40 cm of precision for a measure that everyone can do with a centimeter\nwith a precision of at least 1cm? <\/p>\n\n\n\n The answer is much more complicated than the question. To know what the\nmeaning of the word location is to go back, stopped to stop far back. <\/p>\n\n\n\n But I give you a part of the answer right away: the location of the pipe\nis not made according to the sidewalk, or any other remarkable element near the\npipe. <\/p>\n\n\n\n First text to know: <\/p>\n\n\n\n Order of 16 September 2003 on precision classes applicable\nto categories of topographical work carried out by the State, local authorities\nand their public establishments or carried out on their behalf<\/a> <\/p>\n\n\n\n The text defines two types of objects, point objects and linear or\npolygon type objects. For these second, the localization concerns the\nidentifiable points which construct the lines or the polygons. The location of\na point, according to this order, is as follows: <\/p>\n\n\n\n 7.1. Point geographic objects <\/p>\n\n\n\n If the specifications indicate, some geographical objects may be\nconsidered as punctual. They are then determined by the planimetric and if\nnecessary altimetric coordinates of their reference point. The accuracy class\napplies to the difference between the coordinates obtained for each point by a\ncontrol measure and the coordinates provided for those points; the possible\nsupport points and canvases included in the survey being excluded from the\npoints tested. <\/p>\n\n\n\n [\/ stextbox] <\/p>\n\n\n\n Now our sidewalk has disappeared and we have to provide planimetric\ncoordinates. In other words, we must provide the latitude \/ longitude of the\npoints constituting our conduct, projected on a plane. <\/p>\n\n\n\n With regard to the accuracy of these coordinates, the text indicates: <\/p>\n\n\n\n 6.1. Total accuracy class <\/p>\n\n\n\n The precision class defined above applies to the differences between the\ncoordinates provided for each point and those obtained for control measures. The\ntotal error results from the composition of the internal errors, the errors of\nattachment, and the error specific to the legal network of reference. Therefore,\nthe total error can not be less than one of these three sources of error, and\nin particular the error of the legal reference network, as specified or as a\nresult of the discrepancies noted. during attachment. <\/p>\n\n\n\n [\/ stextbox] <\/p>\n\n\n\n There I feel that I lose you! The text speaks of three types of error: <\/p>\n\n\n\n
The goal is simple: to reach in 2019 to know with certainty the location of all that runs under our feet … For more security and reliability.<\/em> \u00a0\u00bb <\/p>\n\n\n\n<\/div>
\nA structure or section of a structure is classified in Class A if the maximum\nuncertainty of location indicated by its operator is less than or equal to 40\ncm if it is rigid, or to 50 cm if it is flexible. The maximum uncertainty is\nraised to 80 cm for underground civil engineering works attached to\ninstallations intended for the circulation of railway transport vehicles or\nguided when these structures were constructed before 1 January 2011.
\nClass B<\/strong>
\nA structure or section of a structure is classified in class B if the maximum\nuncertainty of location indicated by its operator is greater than that relative\nto class A and less than or equal to 1.5 m.
\nClass C<\/strong>
\nA structure or section of a structure is classified in class C if the maximum\nuncertainty of location indicated by its operator is greater than 1.5 m, or if\nits operator is not able to provide the corresponding location <\/p>\n\n\n\n<\/div>
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