<div dir="ltr"><div dir="ltr">I'm certain someone is going to be more knowledgeable than I, but I do sometimes go back to this answer at GIS.se to get some insight.<div><br></div><div><a href="https://gis.stackexchange.com/a/95397/1297">https://gis.stackexchange.com/a/95397/1297</a><br></div><div><br></div><div>The user shares some formulas for obtaining both the scale and z-factor.</div><div><br></div><div>For other ellipsoids (the answer uses WGS84) it's a matter of determining the length of one degree (longitude) at the equator in metres. For WGS84 it's 111320m for example.</div><div>The longitude is from the center of the area of interest.</div><div><br></div><div><br></div><div>Donovan</div><div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr">On Thu, Nov 8, 2018 at 8:22 AM Nicolas Cadieux <<a href="mailto:nicolas.cadieux@archeotec.ca">nicolas.cadieux@archeotec.ca</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
I am writing to python code to calculate the length (in metres) of a <br>
degree of longitude at a certain degree of latitude. I would like to <br>
take various ellipsoid in mind (WGS84, GRS80, Clarke 1866...). The goal <br>
is to find the right scale (or z factor) when making slope or shade <br>
raster models when x and y are in long/lat and z in feet or meters. Can <br>
someone point me in the right direction to do this in using Proj? Is <br>
Proj the best option for this?<br>
<br>
Thanks,<br>
<br>
Nicolas<br>
<br>
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