Compressing PNG images with pngout, optipng, and advpng

Screenshot tools for Linux and macOS generally produce image files in the .png file format. PNG is a lossless compression format, meaning that it can be compressed without losing quality, which is unlike another commonly used image format, JPG. There are 3 command-line tools which can be used to compress PNG files, pngout, optipng, andContinue reading Compressing PNG images with pngout, optipng, and advpng

Using LIDAR ground points to generate a DEM (Digital Elevation Model) and Contours using PDAL and SAGA

Global elevation data is available through NASA’s Shuttle Radar Topography Mission (SRTM) program. For those interested, this blog post compares the resolution of elevation slope maps derived from the SRTM project vs. LiDAR data, and provides a brief background behind the two methods. LiDAR, in short, provides for much higher resolution Digital Elevation Models (DEMs).Continue reading Using LIDAR ground points to generate a DEM (Digital Elevation Model) and Contours using PDAL and SAGA

Converting LIDAR .las Point Clouds for Viewing in SAGA GIS using PDAL

Recent versions of SAGA GIS no longer support importing files in the .las format. However, a .las file can be converted using PDAL’s writers.text module into a text file format, which in turn can be imported in SAGA. For this example, we will begin with a .las file projected in a state plane CRS thatContinue reading Converting LIDAR .las Point Clouds for Viewing in SAGA GIS using PDAL

Reprojecting LIDAR .las files – Latitude/Longitude to State Plane Example

Download one or more lidar tiles: wget https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/5008/20131013_usgs_olympic_wa_10TDT310990.laz Note the source crs (coordinate reference system, i.e. projection). This 2013 USGS Lidar: Olympic Peninsula (WA) Point Cloud dataset from NOAA uses EPSG 4269. This means that the point cloud coordinates are using latitude/longitude, which is not well supported by many downstream GIS tools. Running lasinfo https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/5008/20131013_usgs_olympic_wa_10TDT310990.lazContinue reading Reprojecting LIDAR .las files – Latitude/Longitude to State Plane Example

TeamViewer: Remote Desktop to Android Tablet

In the past, I’ve written about different remote desktop products/solutions, including NoMachine for remoting into traditional desktop machines, but also a few alternatives for accessing and controlling Android devices from a computer. Today I’d like to mention TeamViewer, a product free for non-commercial use that supports computer to computer, Android to computer, and computer toContinue reading TeamViewer: Remote Desktop to Android Tablet

Shrinking/Compacting VirtualBox Disk Images

Download the SDelete program provided by Microsoft onto your Windows Guest machine. Clean up unnecessary files and programs. One useful utility is WinDirStat. Run the following command in the terminal to write zeroes over unused disk storage in your Windows guest: sdelete64 -z c: Shut down your VM and run the following command on yourContinue reading Shrinking/Compacting VirtualBox Disk Images

Laser Tree Height Calculator – a simple Android app

Tree heights can be approximated to a fairly high degree precision using a laser rangefinder, presuming that one obtains accurate measurements, using a method known as the laser sine method . While some rangefinders made specifically for forestry purposes may have a built in height calculator, I personally own a more inexpensive model that doesContinue reading Laser Tree Height Calculator – a simple Android app

Firefox ‘Task Manager’ similar to Chrome’s

A useful feature native feature of Chrome is its ‘Task Manager’, which allows one to monitor all Chrome processes and their resource consumption: Firefox has been slow to adopt parallel functionality, though this is mostly that multi-process mode in Firefox hadn’t become available until recently (at least in non-Nightly releases). One still needs to installContinue reading Firefox ‘Task Manager’ similar to Chrome’s

How to Install macOS Sierra on VMware Player 12.5

Enroll in Apple’s Beta Software Program. Download a fresh copy of VMware Workstation Player for Windows or Linux from the official VMware site. The free trial of this product has no expiration if used for non-commercial purposes. You’ll need to unlock your installation of VMware to use Mac operating system as a guest following theseContinue reading How to Install macOS Sierra on VMware Player 12.5