# Finding Distance

Global Mapper UserTrusted User
edited August 2014
Hello,
I have a map that I am trying to Georeference. The map has a start point listed as a GRS point however everything is mapped in 500ft. squares off of that point. I was wondering if anyone knew of a formula, program, or web site that could help me find these other points on the map. As I said I know the beginning point so I would need to subtract 500 feet south for another point, add west 500 feet for another point, etc. Hopefully there is a simple solution for this because its been racking my brain on figuring out how to map it.

Thanks,

Han

edited February 2012
Han,

What does your GRS point coordinate look like? Would it maybe be easier to just geo-reference against some other known source (like those available via File->Download Online Imagery/Data) rather than trying to calculate new points based off the others?

Thanks,

Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.globalmapper.com
• Global Mapper User Trusted User
edited February 2012
The point is: N34* 0.795 W86* 19.406

Unfortunately I cannot reference it off some other known source since it is a mine map. I will have to use the grids off of that one point that is listed.
edited February 2012
I would suggest converting that point to a coordinate in some good grid for that location (maybe an orthographic projection with the center lat/lon at that location), then you can just add the 500 feet for the grid to get the coordinates for another grid point for rectification.

Thanks,

Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.globalmapper.com
• Global Mapper User Trusted User
edited February 2012
I would suggest converting that point to a coordinate in some good grid for that location (maybe an orthographic projection with the center lat/lon at that location), then you can just add the 500 feet for the grid to get the coordinates for another grid point for rectification.

Maybe i'm not understanding you correctly. I'm not sure how to add 500 feet to lat and longitude. How do i convert the degrees, minutes, and seconds to feet?

Thanks,

Han
edited February 2012
Han,

You would have to convert your lat/lon to a projected system, like an Orthographic or Transverse Mercator centered on your lat/lon, then add the 500 feet to that. Actually if you create an Orthographic with the center lat and lon at your lat/lon of interest, then the projected location of that would be (0,0) and you could easily add 500 to that to compute projected coordinates for the other points.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.globalmapper.com
• Global Mapper User
edited August 2014
Hello,
I have a map that I am trying to Georeference. The map has a start point listed as a GRS point however everything is mapped in 500ft. squares off of that point. I was wondering if anyone knew of a formula, program, or web site that could help me find these other points on the map. As I said I know the beginning point so I would need to subtract 500 feet south for another point, add west 500 feet for another point, etc. Hopefully there is a simple solution for this because its been racking my brain on figuring out how to map it.

Thanks,

Han

Thanks dude.. Actually, I've same issue but now resolved. Thanks for your help..