Comparison - LINZ 1:25,000 Map to EVS Map

I have been told by more photogrammetrist and cartographic professionals that Landsat ETM+ imagery is only reliable, for map production, between 1:125,000 and 1:62,500. Anything larger would not be cartographically sound. Good soul that I am, I believe them.

I understand that this imagery has pixel resolution reputed to be 14.5-meters at best. The way it has been explained is that each pixel resolves 14.5-meters of the earth, rendering Landsat ETM+ imagery as a satisfactory base from which to create maps at scales between 1:125,000 to 1:62,500.

It seems that Land Information New Zealand (LINZ) did not get the memo. Their Palmerston Atoll map, which I use throuhout this comparson, shows the same shoreline twists and turns my EVS Landsat ETM+ derived map does. They claim their map scale is 1:25,000 and without hesitation offer it to the world.

Close comparison of my EVS precision map and the LINZ Palmerston Atoll map are strikingly similar. Our shorelines are nearly identical. Our depiction of vegetation and reef layers are near mirror images.

I asked a representative of the LINZ cartographic group if Landsat ETM+ imagery was used in the production of their Palmerston Atoll map. He promised to get back to me with an answer. He never did. I suspect that LINZ cartographers used Landsat ETM+ imagery as an important foundational layer in the production of their Palmerston Atoll map. I, on the other hand, used Landsat ETM+ as my ONLY foundational layer.

So, all of you photogrammetrist and cartographers that are convinced Landsat ETM+ should only be used to produce maps at scales of 1:62,500 and smaller should explain to the LINZ cartographers that their 1:25,000 scale maps are not sound or, perhaps, give more credibility to Landsat ETM+ imagery. It seems that Landsat ETM+ base imagery can be made to work at 1:25,000 and EVS precison mapped shorelines are damn good!

Enjoy!