OpenSourcer Posted February 22, 2011 Share Posted February 22, 2011 Hi. I have a dxf file from a client created using autocad. I have no idea what these coordinates mean -40 558.37E and -46 244.43 N. These are UTM? I need to convert to decimal degrees. How do I do this?? Quote Link to comment Share on other sites More sharing options...
CyberAngel Posted February 22, 2011 Share Posted February 22, 2011 Without more information, it's hard to tell what's going on. Do those coordinates belong to a point or a line? Is the space a separator, the way they use a comma in the US, or are there actually four numbers? By "decimal degrees" do you mean you want latitude and longitude or surveyor's bearings? It's possible to import points that are given as northing and easting, then redefine your units as lat/long. Quote Link to comment Share on other sites More sharing options...
OpenSourcer Posted February 22, 2011 Author Share Posted February 22, 2011 Thanks for replying so soon. I managed to extract the data into excel and this is what I got. All the coordinate values are of this format which I assume is an autocad format. I do not have AutoCAD so I cannot do any conversions using AutoCAD. I want to work in decimal degrees as I have to project the coordinates (be it lines, polygons, etc) in google earth as well as add it to my database which accepts decimal degrees. Your help is appreciated. Thanks. x y -38034.2924163296 -48867.3372111626 0 0 SiltTraps -38013.678428361 -48847.8046473652 0 0 -37996.5068603859 -48832.2203675267 0 0 -37964.8317044261 -48828.9999965541 0 0 -37946.2132784493 -48834.7376294894 0 0 -37906.8326254954 -48848.147311339 0 0 -37838.5683475833 -48844.9691993583 0 0 Quote Link to comment Share on other sites More sharing options...
eldon Posted February 22, 2011 Share Posted February 22, 2011 It is quite unusual to have negative coordinates in a UTM system. The datum of each zone is chosen so that all coordinates are positive. Could you reveal where in the world the site is, and someone might get some inspiration Quote Link to comment Share on other sites More sharing options...
OpenSourcer Posted February 22, 2011 Author Share Posted February 22, 2011 datum is Lo 31, coordinate system clarke 1880. It is in africa. I just cant seem to understand these values. At a total loss Please help!! The above values are x and y coordinate values. But What coordinate values I have noooo idea!! Quote Link to comment Share on other sites More sharing options...
eldon Posted February 22, 2011 Share Posted February 22, 2011 Does this look like the place? Not very good resolution in Google Earth. Quote Link to comment Share on other sites More sharing options...
OpenSourcer Posted February 22, 2011 Author Share Posted February 22, 2011 0°25'42.88"S 30°38'59.16"E These are the exact coordinates Quote Link to comment Share on other sites More sharing options...
OpenSourcer Posted February 22, 2011 Author Share Posted February 22, 2011 Rather the coordinates fall witin this area. ;-) Quote Link to comment Share on other sites More sharing options...
eldon Posted February 22, 2011 Share Posted February 22, 2011 I have run out of inspiration, but using Google Earth, your coordinates are about 38000m west of 31degreesE and 48000m south of the Equator. The central meridian of zone Lo31 is 31 degrees east. Usually the central meridian is given a coordinate of 50000e so that coordinates do not go negative. As I have only worked in the Northern Hemisphere, I have only been using positive coordinates. So I would guess that your coordinates are in metre units from a point 31°E on the Equator. Negative going Westwards, and Southwards. I am not sure why you have 10 places of decimals, rather too many for practical use. Quote Link to comment Share on other sites More sharing options...
Jack_O'neill Posted February 22, 2011 Share Posted February 22, 2011 If someone on here has Autocad Map 3d, you could get them to convert your coordinates from the Clarke 1880 system to WGS 84 according to this: http://forums.autodesk.com/t5/AutoCAD-Map-3D/Datum-conversion-Clarke-1880-to-WGS84/td-p/2535281. Failing that, there is a converter here http://www.rcn.montana.edu/resources/tools/coordinates.aspx As a side note, the Clarke 1880 system is also referred to as the "Cape" coordinate system for those who might be more familiar with that term. Quote Link to comment Share on other sites More sharing options...
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