Spatialite and Excel on talking terms
Posted by Micha Silver in GIS, Spatialite on January 25th, 2012
The recent stable version of Spatialite, 3.0, supports linking to and importing Excel spreadsheet tables. Read on to see how it’s done.
My Acacia seedling
Posted by Micha Silver in Acacia Trees, Mountain Biking on December 14th, 2011
Last week’s bike ride was out to the wadi where “my” acacia seedling is struggling to survive. I was very satisfied to see that, with the cool winter weather, the plant has become green and seems to be doing well. On my last visit, during the scorching summer months, the seedling looked totally dried out and dead, and I wasn’t sure it would pull thru. We haven’t had any rainfall yet, just the lower temperature was enough to allow the plant to start growing again. These thorny buggers have eons of evolution behind them, so I guess they know how to deal with the arid season. I’ll visit again later during the winter and take measurements.
Storks over the Arava
Posted by Micha Silver in Israel, Mountain Biking on September 14th, 2011
This week’s morning bike ride took me west of the Arava highway along the trail called the “springs route”. I came across a small flock of storks – maybe 50-75 – still resting on a knoll, getting organized for today’s leg of their migration to Africa. As I approached, they lifted off and resettled further from the trail. Later in the morning, as I came out of one of the canyons, I was surprised by one of those impressive sites we get only in the fall: those few storks were part of a huge flock circling overhead, looking for thermals to gain some free altitude before their day’s flight south. Hundreds, maybe more than a thousand of these majestic birds, moving around in chorus.
It’s early September, a bit soon for large migrations. The Bedouins say that when the storks fly across earlier than usual, then Europe will be experiencing a severe winter.
Spatialite GUI on Enterprise Linux 6 systems
Posted by Micha Silver in GIS, Open Source on September 8th, 2011
Continuing my last post on using the spatialite tools and software on EL 6 and clones, here’s how I got the spatialite_gui to work.
Get your GPS locations into Spatialite
Posted by Micha Silver in GIS, GPS, Open Source on August 31st, 2011
Spatialite, built on the shoulders of the popular sqlite single-file database, offers a broad feature set of GIS analysis tools. Getting data into a spatialite database is a snap when you’re starting from a shapefile. But what about GPS data. Here’s a few tips on how to upload data from the standard “GPX” format into a spatialite DB.
Clipping a raster with GDAL
Posted by Micha Silver in GIS, Open Source on August 25th, 2011
Tim Sutton’s excellent post from last year gives a recipe for creating a professional looking color relief background map from elevation data, and using only GDAL tools. I’d like to suggest one additional procedure to his step-by-step guide.
Getting GPS data into Scientific Linux 6.0
Posted by Micha Silver in GIS on May 21st, 2011
The tried and true (command line) program for interfacing between GPS instruments and Linux workstations is gpsbabel. QGIS and GRASS for example use gpsbabel to pull waypoints and tracks into GIS layers. However, to get gsbabel working on Scientific Linux 6.0 requires jumping a few hurdles
GRASS 6.4.1 on Scientific Linux 6.0
Posted by Micha Silver in GIS, Open Source on May 15th, 2011
The latest stable release of GRASS GIS is 6.4.1. Binaries are already available for several operating systems and distros, but not yet for RHEL 6 or its clones. With the legwork done by the folks at FedoraProject, we can prepare RPMs and install GRASS with little ado also on SL6
Are acacias really dying out?
Posted by Micha Silver in Acacia Trees, Israel on May 6th, 2011
The Acacia is one of the few indigenous trees that survives in the harsh conditions of the Arava region of southern Israel. With global warming accelerating, some environmentalists have voiced concern that acacia stands are drying up. However almost no research is being done on natural regrowth.
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Clipping Satellite Images at the Coastline
Posted by Micha Silver in GIS on March 25th, 2011
Raster data from satellite born sensors will, in most cases, cover the land areas and oceans as well. If the satellite data is intended only for background imagery, then having the sea areas appear is fine. However, when the data will be put thru some GIS analysis, the sea areas can actually interfere. Here’s a simple method, using GRASS GIS to clip out only the land surface.