Comments for Alastair Aitchison

Comment on The Google Maps / Bing Maps Spherical Mercator Projection by Niklas

Niklas — Mon, 03 Apr 2017 14:17:59 +0000

Hi Alastair,
many thanks for the quick reply. I did realize that this blog did not include UTM – but once I got WGS84 geographic I should manage to further convert to UTM. it is the part Web Mercator – WGS84 that I need. I don’t understand what x and y are, i.e. what the units are. The information I get when downloading a bing map is also lat /lon in degrees but x and y seem to be much larger numbers if I convert lat lon from Mercator WGS84 to Web Mercator.

Comment on The Google Maps / Bing Maps Spherical Mercator Projection by alastaira

alastaira — Mon, 03 Apr 2017 10:40:55 +0000

In reply to Niklas.

Hi Niklas,

No part of this article is related to UTM projection – it’s about converting from WGS84 geographic coordinates to Web Mercator projected coordinates. If you want to convert to one of the UTM zones I recommend you use GDAL.

Comment on The Google Maps / Bing Maps Spherical Mercator Projection by Niklas

Niklas — Mon, 03 Apr 2017 10:26:18 +0000

Hi Alastair
I am one of those users that just need a map transformation as a one off without knowing enough about projections. I need to transform a bing map into utm.
Feeling very stupid – but in the two sets of formulas you provided, what are x and y? they are too large for conversion factors, too large for being lat/long in wgs84, and not correct for being x and y in utm…
Sorry for the stupid question, but your help is much appreciated, thanks!

Comment on Animal Crossing Curved World Shader by Pete Loco

Pete Loco — Sat, 18 Mar 2017 20:34:25 +0000

This is very impressive. When I’m done coding the project I’m doing this for I’ll show it to you and blow your mind. Thanks a lot!

Comment on Importing DEM Terrain Heightmaps for Unity using GDAL by DE CLARKE

DE CLARKE — Mon, 13 Mar 2017 04:41:14 +0000

I am a newbie at this (just learning Unity, actually). I have obtained GIS heightmap images from a couple of different sources: terrain.party, and official Canadian government web site. My problem is probably a classic newbie issue. I am getting, say, a 1024×1024 image from my source (after conversion using gdal). At one pixel per Unity unit, that’s only 1km on a side (one Unity unit seems to scale to one metre). But the area I’m trying to model, say an island and its immediate vicinity, might be 30 km on a side (the data I requested from the source). The GIS data seem to be very coarse in scale, low-rez compared to the quality I was hoping for to build a 3d sim of the area. The resulting landscape looks “blobby” and unrealistic when viewed at the scale of the FPS camera, especially coastlines. Is there a way to improve this? I had thought of applying some aggressive upsampling to the original image but wasn’t sure what artifacts might be introduced.