[Therion] Multiple fixes for the same point

[Xavier Pennec]

One of the problem for a predefined accuracy of gps measures is that it 
really depends on each measurement. I usually use a stddev of 2 to 3 
times the figure of merit (FOM) of the GPS averaging procedure for x and 
y coordinates and 4 to 5 times for the altitude. This can range from a 
few meters (this has  to be on a plateau with no trees) to 50/100 m for 
measurements in forests with a few satellites only (there are also often 
reflections on cliffs that perturb the measure).

Xavier

Le 11-Sep-17 à 19:10, Benedikt Hallinger via Therion a écrit :
> No, i meant the following:
>
> currently one has to give std-dev explicitely:
>  fix 1.2a  0.5 0.5 0.5
>
> it would be nice to use instead:
>  fix 1.2a  gps
> where the term "gps" is some predefined accuracy, like in grade 
> definition
>
>
> Am 2017-09-11 10:08, schrieb Bruce Mutton via Therion:
>> Benedikt wrote
>>> The option to use "alias names" for fixes instead of directly 
>>> numbers would be good, this would allow to ship standards with 
>>> therion and allow the user to to define custom ones, just like in 
>>> grade definitions.
>>
>> Not sure I understand correctly what you mean.
>>
>> We can make alias now, using equate.  This is what I usually do for 
>> gps fixes.
>>
>> In a cave survey 'index data file'...
>> centreline
>> cs lat long
>> fix gpsEntrance01 <lat> <long> <altitude> [<stderr> etc ]
>> fix gpsEntrance02 <lat> <long> <altitude>
>> etc
>>
>> equate gpsEntrance01  53@<survey1>
>> equate gpsEntrance02  1@<survey14>
>> equate gpsEntrance01  AliasNameCreatedByThisStatement
>> endcentreline
>>
>> ie 53@<survey1>, gpsEntrance01 and AliasNameCreatedByThisStatement 
>> are all alias' of each other. They all refer to the same physical 
>> point. The last name is created by the equate statement, whereas the 
>> others all exist prior to the execution of the equate statements.
>>
>> Or were you meaning something different?
>>
>> Bruce
>>
>>
>>
>>
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>
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