[GIS] Georeferencing to x y coordinates with one lat long origin

Question

We are running parallel transect lines for a survey, which will roughly cover a rectangular area. When making the transects, we will periodically capture spatial locations of features and events we encounter.

Due to technical issues, we can only record the latitude/longitude coordinates of the very beginning of the first transect (i.e. one corner of the rectangle). The locations of all our logging of other features/events will be recorded relative to the origin, with x y coordinates (running along the east-west north-south axes, respectively).

I would like to georeference all our data points from the survey into a map, where I can click on any data point and get its coordinates in latitude and longitude.

How should I do this?

I prefer a solution that could be done in QGIS 1.7+, but ArcGIS 10 is OK, too.

Answer 1

When you say "the locations of all our logging of other features/events will be recorded relative to the origin" I assume you mean in some planarlinear measurement (lets use meters in this example). The steps you would take, assuming your data is in a spreadsheet, are as follows:

1. Project your lat/long into a local meter projection (this will depend on your location). Find the easting and northing.
2. Take your other relative measurements and add/or subtract them to the origin's easting and northing in the spreadsheet.
3. Import your spreadsheet into ArcGIS using the "Add XY data tool" (or equivalent tool in QGIS) and specify the projection you used in step 1.
4. Reproject your data into WGS84.