How to calculate pixel size on image of map?

Question

I have to save to .png file with part of map from app.
I've got information about PPI, easting/northing, print resolution, map scale and map coordinate system and using this information I have to calculate a size of pixel (in meters) given information about curvature of the earth. I have to know how many meters on earth is representing by one pixel on my picture.
I was trying to find any pattern for that but without success.
Anybody here know how can I calculate that?

CAMHN · Answer

A simple method to measure pixel length is to zoom the image of the map until you can identify each pixel cell, then using the ruler you can get the size of it. For example I'm using Qgis, but you must georeference the map in order to get the true length.

Nicolas Cadieux · Answer

Gdalinfo or raster information in processing toolbox will give you that information if the image is georeferenced.  You can also find the information in the layer properties.
If you don’t have QGIS, you can use Gdal info from the command prompt.
https://gdal.orgprograms/index.html
If not (max x coordinates -x min coordinates) / x pixels

How to calculate pixel size on image of map?

2 Answers

Add your own answers!

Ask a Question