Latest Contributions by GeorgeDurkee1

Zach: Hi. I just replied to Dan that I've not yet tried the cluster analysis but will later this week so, short answer, I'm not sure if I have a solution or workflow. So, probably TMI about stuff you might already know but: The historical fire record has fire polygons since 1900 or so. What we're looking for are clusters of fires driven by Foehn type winds in the Sierra Nevada mountains of California. I'm thinking the clusters might be a proxy for Foehn events.That information isn't captured in the historical data set (though there are a few papers on recent wind events). From that subset it's then a little easier to narrow a search of newspapers and the USFS archive on those dates or years to see if there were high winds or the fires were just coincidentally on the same day (not uncommon, of course) but just not driven by high winds. I'm also looking at the shape of the fires. Long and narrow perimeters might indicate a fast moving wind-driven fire. There's a bunch of those around the Tahoe area but, as you go south, they're more amorphous blobs. This is in keeping with, apparently, fewer Foehn wind events occurring south as the Sierra rises in height. Also, many of the pre ~1970s records often don't have a start date only a year, so shape could be a proxy for wind. One of our crew of retired GIS geeks has written a paper looking at fire insurance cancellation by county, forcing people to use the Fair Plan. The greatest threats of catastrophic loss (for both insurance companies and, of course, residents) is from these wind driven fires but cancellations don't seem proportional to that risk by county. As above, risk seems to decrease as you head farther south so we're trying to find other events in the historical record to confirm this. For instance, there was a major set of fires in 1936, most of which aren't mapped. Newspaper newspaper accounts describe a number of fires on the same day from Tahoe south to Mariposa as well as a couple in the coast range. Anyway, I'm kinda flailing here but  always open to thoughts & suggestions! Thanks, George ... View more

Dan: Thanks. I think the cluster analysis is the most promising. It'll be a couple of days before I can start tinkering with it. Unless I'm missing something (and that's always a possibility!), I think selecting by attribute and creating a layer would give an overlap of the same date across any year where I want a unique date & year. Anyway, I'll post if your solution is right later this week (I hope..). Thanks again! George also sort of retired ... View more

Hi. No. It's especially weird because it seems to only happen with the lidar dataset I've been working with for Tuolumne County, CA. But when I've used the Yosemite National Park lidar and reclassified height (from the default) in an LASD set, it goes fine. Also, as mentioned, it works fine on the Tuolumne set if I reclassify each file individually, just not as a set of, say, 5 in an LASD. With Yosemite I did a 15 file LASD at once and, while it took forever, it worked with no errors. So, what are the commonalities with your dataset and mine? That must have part of the answer. I'll keep struggling and hope you or another community member can come up with a solution. Thanks. George ... View more

Cody: This is great. Many thanks! Among other things in your answer, it's good to know some lidar sets come with ground classified. That seems to be true of the one I'm using (2021 of a county) so, as you suggest, probably no need to reclassify. The DSM I created seems to match well with the terrain. Anyway, if your friends have any other suggestions, I'd really appreciate them. Fortunately this isn't part of my job, but lidar gives some great ability to visualize and analyze terrain. Other than the learning curve, it's kinda fun... . Thanks again! George ... View more

Yes, I think that was it. Thanks! I know I did it after it was answered here but, heh, forgot because I didn't need it. I'll copy and paste this one into my ongoing 'notes of stuff I'll probably forget'.... . Thanks again! ... View more

Arrrgh! I could have sworn I put that in my notes (teaching a class...). But it's not there and, with memory like a sieve, I forgot how except that, once I saw it, it was pretty easy. That doesn't help you at all, does it? I'll keep looking in my notes. But maybe @Tim_McGinnes remembers?? I also remember I asked some fire mapping people and they didn't know either, which was kinda worrisome... . ... View more

Last time I had this I found arcgissharingserver in Processes. For some reason, this time in was in Details (within Task Manager). So I ended it there and it worked. Now happened twice, this time trying to share a tiled tiff... . 2 hours for a small file -- enough... . ... View more

I'd been having this problem off and on for a few years though had only installed ad-block a year or so ago. When working with AGOL I usually switched to FF. Found this thread and, good news, I disabled Ad-block, refreshed, and Share options came up. Still, seems like a not unusual problem that should be solved at a higher level. PS: @JoeFlannery's post is the solution. ... View more

Yay. That's it. Solved both identify and the link solved the color problem. Many thanks! George ... View more