Contact Contour & Grid

Corrections, questions and ideas for new map and GPS calculators are welcome. Email logan.luo@adsnova.cn; we usually reply within a few working days.

Reporting a Calculation Problem

Please include:

• The calculator and every value you entered, exactly as you typed it, including signs and hemisphere letters
• The datum and grid of the map or device you are comparing with, such as WGS84, NAD27, NAD83 or OSGB36
• The result you expected and where it came from, such as a GPS unit, a GIS program or a printed map
• For areas, the list of corners in the order you entered them

Other Grids and Datums

Our tools work in WGS84 and UTM. National grids such as the British National Grid, MGRS or State Plane coordinates need datum transformations and grid parameters of their own. If you would like one supported, tell us which and where its parameters are published.

Suggesting a Calculator

We are considering tools for magnetic declination, MGRS references, destination points from a bearing and distance, and geohashes. Tell us which you would actually use and for what.

What We Cannot Help With

We cannot locate a person, confirm a property boundary or provide survey advice for a legal matter. In an emergency, call your local emergency number and give your position in the format the operator asks for.

Accessibility

If a calculator is hard to use on a phone in the field, with a keyboard or with a screen reader, tell us the page and device; we treat these as bugs.

Response Times

We aim to reply within five working days and prioritise reports of a wrong calculated result, because a wrong coordinate can send someone the wrong way.

Privacy and Copyright

See the Privacy Policy and DMCA Policy. Please put "Privacy" or "Copyright" in the subject line.