Author Topic: Setting up a true coordinate system  (Read 172 times)

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dubb

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Setting up a true coordinate system
« on: June 22, 2017, 12:25:39 pm »
I would like to know how to set up the coordinate system in AutoCAD 2017 without having to choose a marker location.
My company does not use MAP 3d or Civil 3D, our client sends us cad files that are geolocated we are able to edit them and send them back without gis functionality.
When I insert a client's geolocated drawing into new drawing that I used Geographiclocation command on, the location and aerial image is incorrect.

Mark

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Re: Setting up a true coordinate system
« Reply #1 on: June 22, 2017, 01:30:49 pm »
The coordinates shouldn't matter at all. Where are you getting the aerial imagery from?
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dubb

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Re: Setting up a true coordinate system
« Reply #2 on: June 22, 2017, 01:46:34 pm »
The imagery comes from the "Geographiclocation" command.

Mark

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Re: Setting up a true coordinate system
« Reply #3 on: June 22, 2017, 01:54:15 pm »
Okay, i see what you're talking about now. That is strange.
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Mark

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Re: Setting up a true coordinate system
« Reply #4 on: June 22, 2017, 02:56:01 pm »
The imagery comes from the "Geographiclocation" command.
That's about worthless. I can get the aerial and my xref'd dwg located in the same area but the scaling is WAY off. The aerial is scaled, somehow.
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Mark

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Re: Setting up a true coordinate system
« Reply #5 on: June 22, 2017, 03:11:20 pm »
Okay, got it. I can get my aerial to match my reference dwg, within reason that is. My xref was scaled incorrectly before.

I picked a location from google maps for my lat, long that related to a known point in my reference dwg, in this case a road intersection.
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Mark

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Re: Setting up a true coordinate system
« Reply #6 on: June 22, 2017, 03:16:51 pm »
I can get pretty close by right-clicking on the location map too.
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dubb

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Re: Setting up a true coordinate system
« Reply #7 on: June 22, 2017, 03:44:00 pm »
I am using a trial version of Spatial Manger, btw. I am trying determine whether we should spend the extra $150 licensing map 3d, or purchasing 3rd party software. Majority of our GIS needs can be acheived with QGIS.
This is what I tried.
I exported a point using AutoCAD at 0,0 to google earth as a kml file using SPM (Spatial Manger).
Extracted the point's lat & longs
I plugged those coordinates into the "geographiclocation" script, chose the location as my drop marker.
Once prompted to chose the coordinate system.I can't pick CA83-VI-F (California State Plane Zone 6 Feet). Maybe I have to transform the coordinates because Google Earth uses CRS 3897. That's sort of where I am stuck.
I tried to pick a location manually if that's the only way I guess it will work. Thanks for trying.  :smitten:

Mark

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Re: Setting up a true coordinate system
« Reply #8 on: June 22, 2017, 03:57:16 pm »
what kind of accuracy are you looking for? How are you using the imagery? Have you tried looking for aerials from your local government agencies?
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dubb

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Re: Setting up a true coordinate system
« Reply #9 on: June 22, 2017, 05:19:30 pm »
We use the aerial to trace roads. I import parcels and survey points that are exported from QGIS in dxf format. The accuracy would be +/- 1 to 3 ft.

cadtag

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Re: Setting up a true coordinate system
« Reply #10 on: June 23, 2017, 07:34:55 am »
Get Map, and use real georeferenced aerials.  Bing maps are better than they were, but still suck

Or, look into Dotsoft geolocation tools
The only thing more dangerous to the liberty of a free people than big government is big business

reyas1123

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Re: Setting up a true coordinate system
« Reply #11 on: June 24, 2017, 05:49:11 am »
Try Global Mapper software once you drag your drawing it will ask for georeference location  then export to kml or kmz to google earth.