The only thing I can think of is Google Maps, and select Terrain at the bottom left by clicking on the Satellite Box Layers - See Attached
Then need to zoom in some before the Heights above sea level grad lines appear, ie green circle....
Then can zoom either further for more gradient lines, in increments of 20meters, see 2nd attached,
Note: if zoom in too much, lines may disappear all together,,,
Plus I am not sure how extensive these grad line are around cities, towns or the burbs ?
Hope this is useful - if not, have you tried googling Topographic Map for your area, could be more defined and accurate , there may be a supply somewhere,
