Survey datum needs defined projection ArcGIS 10.1

bibiKhan — Thu, 02 Oct 2014 22:58:35 GMT

I have a survey data for contours. I have got the instruction that I can bring it to state plane by adding easting and northing offsets and dividing by a scale factor. I am stuck. I have tried all the features available in ARCGIS 10.1 under projection and transformation but could not find anything to work it out. I tried calculate geometry but it will give a point file and still cannot bring my data to state plane to match with my other data sets.. My data is contours lines. Any help will be greatly appreciated.

thank you,

bibi

Re: Survey datum needs defined projection ArcGIS 10.1

MelitaKennedy — Fri, 03 Oct 2014 19:34:45 GMT

You may be able to apply the scale factor and offsets to the state plane coordinate reference system parameters to create a custom coordinate reference system.

Let's say we have these instructions:

1. Add 100000.0 m to X(local) and 200000.0 m to Y(local).

2. Divide the results by 1.00003.

X(spcs) = ( X(local) + 100000.0 ) / 1.00003

Y(spcs) = ( Y(local) + 200000.0 ) / 1.00003

So we need to turn this around:

X(spcs) * 1.00003 - 100000.0 = X(local)

Y(spcs) * 1.00003 - 200000.0 = Y(local)

When calculating projected coordinates the last parameters applied are the scale factor (SF) and then the false easting (FE) and false northing (FN) so these are the State Plane equations:

X(spcs) = FE + SF * (protoX)

Y(spcs) = FN + SF * (protoY)

Now, we substitute:

X(local) = ( (FE + SF * (protoX) ) * 1.00003 ) - 100000.0

Y(local) = ( (FN + SF * (protoY) ) * 1.00003 ) - 200000.0

X(local) = (SF * 1.00003) * (protoX) + (FE * 1.00003) - 100000.0

Y(local) = (SF * 1.00003) * (protoY) + (FN * 1.00003) - 200000.0

SF*1.00003 becomes the new projection's scale factor

FE * 1.00003 - 100000.0 becomes the new false easting

FN * 1.00003 - 200000.0 becomes the new false northing

Melita

topic Re: Survey datum needs defined projection ArcGIS 10.1 in Coordinate Reference Systems Questions

Survey datum needs defined projection ArcGIS 10.1

Re: Survey datum needs defined projection ArcGIS 10.1