# 1m cell size equivalent value in decimal degree

I'm doing re-sampling pixel size in ERDAS 2014,I'm using input image(Indian terrain) in GCS_WGS_84 projection. Now I have to keep out put cell size as 1m,what is the 1m equvivalent value in Decimal degree?

• There is no straight answer to your question because it will vary depending on where you are on the globe (especially as you move away from the equator) and therefore will vary across a large continent like India. You may be better using projected SRS with meters as unit. – MappaGnosis Oct 30 '14 at 8:00
• Check out this question: gis.stackexchange.com/questions/7430 It gives some hints on how the scale varies according to the latitude. – julien Oct 30 '14 at 8:17
• Length along one axis does change according to latitude but not along the other axis (it does a little because Earth is not a perfect sphere). If you want to use same pixel size in E/W and N/S directions you can base the calculation on "one degree is 111320 meters on equator". I you want to use non-rectangle pixels read en.wikipedia.org/wiki/Decimal_degrees and play with calculator csgnetwork.com/degreelenllavcalc.html. – user30184 Oct 30 '14 at 8:33

## 1 Answer

Assuming a spherical Earth of radius, R = 6,371,000 m,
and a latitudinal (N-S) arc length, a = 1m,
then the latitudinal arc angle, = a / R = 0.000000157 rad = 0.0000089932 deg,
but note what others have said about the fact that a longitudinal (E-W) arc length of 1m will have a longitudinal arc angle that increases as you move away from the equator.