How-to

Lab Calendar

Submitted by tony on Tue, 2008-03-18 17:44.

The purpose of this calendar is to reserve equipment, and schedule tasks related to the lab.

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Exporting Track Data from Lab Trimble GPS

Submitted by dylan on Mon, 2008-03-17 22:52.

 
GPS Setup

  1. enable "between feature logging"
  2. set the logging interval (time or distance) [this can be changed in pathfinder office]
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Working with Garmin GPS Units and Data

Submitted by dylan on Thu, 2008-02-28 22:26.

Garmin Rhino 120Garmin Rhino 120

Overview

Importing and exporting data from/to the Garmin Rhino 120 units can be accomplished in several ways, resulting in several possible file formats. Care should always be taken to note the spatial reference system used to collect data, and how these data are handled by any import/export software. These units use a serial interface, therefore you will need a machine with a serial port or an appropriate USB serial port adapter. The best has several applications installed, and more information on possible software solution can be found here.

In general it is best to save your waypoint or track data in GPX format, as this format is text-based and can easily be converted to other formats. Most applications will create GPX files using the native coordinate system of GPS (geographic coordinates WGS84 datum). Care should be taken to ensure that any GPX file created (for the purposes of uploading data to a GPS) contain "tags" (attributes) that conform to the standard names the GPS unit expects. Here are the tags that the Garmin Rhino 120 expects:

  • ele the elevation in meters
  • name the name of the waypoint
  • cmt a comment about the waypoint
  • desc a short description of the waypoint
  • sym the symbol to use for plotting (default is 'Waypoint')
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Generation of Vegetation Sampling Areas

Submitted by dylan on Wed, 2008-02-27 20:06.

 
Premise:
We need some randomly selected areas for performing a vegetation survey. Two possible approaches are given: random selection of grid cells from a 7x7 grid superimposed over the region of interest, and random generation of 100x100 meter blocks which meet certain criteria on how close they can be from each other and the edges of the region. The region and grid files are attached at the bottom of this page.

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Canopy Quantification via Image Classification

Submitted by dylan on Tue, 2008-02-19 21:14.

 
Premise:
Supervised classification of 2005 NAIP imagery (1 meter resolution) into 3 classes (grass, tree, shade), by the SMAP[1-3] algorithm. Tree heights are small compared to horizontal extent, and therefore "shadow" pixels can probably be interpreted as "tree" pixels. Field verification will be needed to check actual percent coverage of classes, and fractionation of tree species within the "tree" pixel class. Still looking up the specific date/time the source imagery was taken. Since the shadows appear to be falling north-ward, the photo was probably taken in the morning. The color of the grass suggests that it was probably summer. In these conditions there should be no shading of this region by local terrain features.

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Lab Chromameter (CR-410) SOP

Submitted by dylan on Wed, 2007-10-03 22:24.

Calibration of the CR-410

  1. power on the unit, and press the 'Cal' button
  2. place the unit on the white standard calibration tile

Ordinary Kriging Example: R via text file

Submitted by dylan on Mon, 2007-06-11 01:58.

 
Overview:
A simple example of how to use R to perform interpolation with ordinary kriging, using data from a text file. This example makes use of the gstat library for R. Additional examples of how to use the following gstat functions are included:

  • variogram maps
  • directional variogram plots
  • ploting the interpolated surface directly from R

Ordinary Kriging Example: GRASS-R Bindings

Submitted by dylan on Wed, 2007-06-06 23:00.

 
Overview:
A simple example of how to use GRASS+R to perform interpolation with ordinary kriging, using data from the spearfish sample dataset. This example makes use of the gstat library for R.

 
Helpful References:

  • Issaks, E.H. & Srivastava, R.M. An Introduction to Applied Geostatistics Oxford University Press, 1989
  • GSTAT Manual
  • GSTAT Examples

Code highlighting examples

Submitted by dylan on Thu, 2006-12-14 22:24.

Posting code snippets: style considerations

Several methods exist within the drupal CMS for posting code snippets. The geshifilter module will automatically highlight several languages. The 'R' language is missing, so it might be a good idea to write a language file for it. The geshfilter code block is implemented with the following tags. Note that you must specify the language type: i.e. 'sql', 'bash', 'php', 'python', etc.

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Logistics: Getting Connected and Executing Queries

Submitted by dylan on Fri, 2006-11-03 05:39.

 
Building and Saving SQL code snippets
A simple text editor is the best environment for working on (and saving!) your SQL queries. Linux users are encouraged to use either 'Kate' or 'Kwrite'. Windows users should look into Notetab Light or SciTE. Mac users should check out TextWrangler.

 
Connecting to the database
In general, the simplest way to interact with our composite soil survey database is by connecting to the best with an SSH client. Mac/Linux users have this functionality built-in. Windows users will need to use something like Putty, or Xming. Once an ssh connection with the beast has been setup, you can connect to the database with the following:

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