Create study area map using Imhof style

[Nikolas]

Dear members,

I have the to create a map of India which will be used as the study area map. Because this map will be part of my PhD I want to make it special. And what's more special than the famous Imhof style map.
My study area is the country of India. I downloaded the SRTM region of India and I created a "traditional" hillshade (as John Nelson likes to call it) based on the SRTM.
The problem is that the resulting hillshade seems like salt & pepper (img_1) while I want to achieve something like this (img_2).
What I have tried so far is to upscale the SRTM to 100m but I'm guessing that's not enough.
Any suggestion on how I can make the hillshade to look more like the img_2?

Best wishes,

Nikolas


traditional_mine.png img_1
traditional_nice.png img_2

[waldronate]

You need to filter the image to your final resolution before doing the hillshade. Calculate your desired image resolution and the area that you wish to cover and upscale to that (if you want a 1000 km wide area rendered into roughly a 1000 pixel image then you'll need 1000000m/1000px = 1000m/px resolution. There looks to be a whole lot of aliasing in the first image and the second image looks to be mostly ambient occlusion / texture shading as an alpha channel.

Start by reading http://wiki.gis.com/wiki/index.php/S...20locations%29 (especially the parts on Resolution Bumping) and then move to reading http://www.shadedrelief.com/bumping/bumping.html for good information. Heck, just read http://www.shadedrelief.com/articles.html and you'll know more than you ever wanted to know.

Edit: maybe that second one is just a hill shade with the midtones (grays) set as transparent. Either way, reducing your resolution is the key to getting what you're after.