[rj5316]

Hi ,

when we create locations and specify the lat long of the locationm, in which table does this get stored.

Also what is "other lat/long" in geography within the power data of transport planning and execution AND what is its use? It looks as though these are cities created in the public domain. But if so then why does it allow me to create a same city with diff lat / long ... and any ways the city is not a manadtory feild when creating locations...

rgds--

[james_foran]

LAT and LON fields are in the GLOGOWNER.LOCATION table...

I am not sure what Other Lat/Lon is for though. Looks like a set of defaults or something??

[otmrookie]

I think it is the GEO_POSTAL_POINT table, hope that helps.

[oliver]

lat/long gets stored in the location-table, in fields "lat" and "lon" (Number 10,5).
On the "same city with diff lat/long", usually cities have more then one lat/long, take "Chennai" as an example.
The city isnt mandatory (neither is lat/long), because OTM wont necessarily need it to calculate transit times. But if you want OTM to calculate the distance between 2 Loc's, it needs lat/long to do so; in the background it uses a formula to include the curve of the surface and all these things to calculate the most realistic distance between to pairs of lat/long.


Rgds
Oliver

[rj5316]

Thanks OM,

Understand that the other lat /long are cities created in the public domain and cities have diff lat / longs...but when planning does OTM pick up the lat long from the location table ( i.e as recorded by the user) or from the other lat long (the city one)......

alternatively what is the purpose of the other lat / long....

thanks...

[EmergeNow]

If you create a new location with lat/long, it gets stored in the location table. If you populate the other lat/long tables (GEO_POSTAL_POINT, GEO_CITYPROV_POINT), the location refers to them to look up the lat/long and populate the location table.

For example, I have worked with clients that have purchased the lat/long for every US zip code and I loaded that information in the GEO_POSTAL_POINT table. When a new location was entered with a valid zip code and saved, the lat/long is defined for the location.

[njoyotm]

Hi,

Can anyone help me out in finding wat formula does OTM use for calculating distance using LAT / LON?
I find that the Great Circle Distance Formula is not bringing out the same results as OTM does.

Regards,
njoyotm

[Stefano]

Hi
looking in Database PL/SQL PACKAGES you can find in schema GLOGOWNER
Package GPOINT
inside it the function:
"function estimate_distance(fromLat number, fromLon number, toLat number, toLon number) return number"

this function referring to java code in db (DbGPoint.calculateEstimateDistance), you could open (with TOAD or something similar) and check also the java code .

I haven't test if this function return same values returned by UI, but I imagine yes.

Regards

[njoyotm]

Hi

Thank you very much for the useful information.
I tested the function estimate_distance but there are variations
in the value returned by this function and the value returned via UI.
However many thanks,I am looking into it.
Any suggestions are always welcome.

Regards,
njoyotm