# How can I compute raster pixel width and height given raster bounds, row count, and column count?

Restated, how do I convert arc degrees to meters? For example, I have an elevation data raster that has the following metadata:

``````WEST LONGITUDE=64.97798789° E
NORTH LATITUDE=33.02003415° N
EAST LONGITUDE=66.03338707° E
SOUTH LATITUDE=31.98030163° N
PROJ_DESC=Geographic (Latitude/Longitude) / WGS84 / arc degrees
PROJ_DATUM=WGS84
PROJ_UNITS=arc degrees
EPSG_CODE=4326
NUM COLUMNS=9001
NUM ROWS=9001
PIXEL WIDTH=0.0001111 arc degrees
PIXEL HEIGHT=0.0001111 arc degrees
``````

I can compute by hand the pixel width in arc degrees as follows:

``````(EAST LONGITUDE - WEST LONGITUDE) / NUM COLUMNS
``````

Similarly, I can compute by hand the pixel height in arc degrees as follows:

``````(NORTH LATITUDE - SOUTH LATITUDE) / NUM ROWS
``````

My question is how to compute the pixel width and height in meters.

• Do you have access to GIS software? You could try and project it using meters as the unit of measurement.
– djq
Nov 17 '10 at 22:05
• Thanks for the suggestion. I know how to use Global Mapper, which is where I obtained the sample data above. Through a sequence of steps I am able to use Global Mapper to see the pixel width and height as meters, but it's a hassle, and I want to be able to verify by hand what Global Mapper says.
– Sipp
Nov 18 '10 at 16:02
• I'm sure you're aware that the length of a degree of longitude varies with latitude (from infinitesimally small at the poles to roughly 111 km at the equator). I would have thought that to calculate cell dimensions in meters by hand would be more of a hassle than with e.g. Global Mapper. Nov 18 '10 at 20:12
• That said, take a look at Wikipedia's Great-circle Distance page. en.m.wikipedia.org/wiki/Great-circle_distance Nov 18 '10 at 20:42