quantumsawdust

Substantial roadblocks working with data

Discussion created by quantumsawdust on Sep 25, 2012
Latest reply on Sep 26, 2012 by erice-esristaff
I have run into problems on several fronts for creating data.

My goal is to get a raster dataset of a CA coastline, focusing on the details of the first few hundred feet in elevation.

Plan 1: I have .tif files of sections of the coastline. However, they include high elevation data and I have been unsuccessful in creating data I can look at details with. Using stretched greyscale symbology doesn't create a smooth color gradient - instead I get a series of "bands" of markedly different greys, and nothing I have done has fixed that (though adding hillshade helps, I would like to not rely on that). This is an image of the best image I have managed to create.
[ATTACH=CONFIG]17974[/ATTACH]

Secondly, I have downloaded .LAS LIDAR files www.opentopography.org (CA_SantaBarbara-Ventura_2005). These would be great to work with, but I have been unable to convert them into a usable form. I have followed my intuition (which didn't work) and I have followed the guidelines on this site (which also didn't work). The guidelines on that site would result in either an error, or an empty 0 kb dataset.

Here are my specific wishes:

In the first case, I would love to know how to display the data as a perfectly smooth grey-scale gradient. I would also like to know how to clip off values from the dataset (so, say, I could remove all elevations >500 meters from the dataset). Both of these would help me a ton.

In the second case, if anyone happens to know why the guidelines on the site I linked are not working, I would very much appreciate it. I followed them exactly, word for word, so I assume they are outdated or that they don't work universally for .LAS datasets.

Thank you very much for your time

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