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Tips and Tricks for linking data in ArcGIS

There are two basic types of joins in GIS tables and geo-data: spatial and relational (based on table IDs). Spatial join is the key concept in GIS and that is what sets all GIS technologies apart from other relational databases. Here we start with performing relational joint of list of zipcodes with names to the US zipcode shapefile.

Relational Join

To join table to shapefile based on ID (zipcode) the data type in the column you are planning to join should be the same. Let’s check on data type in Zip code shapefile. Right click on shapefile, select properties and look under Fields tab. The format of the data is Text and size is 5 digits.

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Converting multiple KML files into geodatabase for GIS project in ArcMap Desktop

Google Earth is wide-spread free GIS application which allows users to draw their own point, lines and polygons. Very often users create many separate files in KML or KMZ format and upon moving to the next step in GIS analysis are trying to recreate the same geographies in ArcGIS editing software. The fastest way to bring all those custom data into GIS project is described here. Assuming that you have Google Earth and ArcGIS Desktop 10.2 installed, bring all the KML/KMZ files into Google Earth through File\Open (you can select multiple files from the same folder):

2D Dipole-Dipole Electrical Tomography with LandMapper

Manual measuring of electrical resistivity 2D cross-section is possible with LandMapper with supplied (optional) or made by user cable set.

There are two modifications of 2D cable set offered and tested by Landviser, LLC:

  1. Mobile shallow (~2 m depth) set consisted of two T-style probes (AB and MN dipoles) similar to mapping probes. The dipoles are set at 1 m size with possible separation between dipoles (wire length) no more than 5 meters (n=5).
  2. Stationary set (~ 14 m depth) where electrodes are hammered on the soil surface along the straight line at one meter distance. Electrodes are simple metal spikes/nails and is sourced locally (are NOT provided by Landviser, LLC). We supply wires with banana-plug connections to LandMapper terminals on one end and alligator clips on the other end to connect with electrodes.

Principle of measurements with both sets is the same for both cable sets and is illustrated by figure below. You can also watch instructional videos on our YouTube Channel - LandviserLLC

Location

0° 34' 51.8304" N, 71° 51' 2.1096" W

Building geodatabase in ArcMap 10 Desktop

Those step-by-step tutorials are created for novices in GIS. By design, they are very simple and provide only essential and practical information to accomplish most common tasks with GIS software. For in-depth coverage of the topic, please, refer to ESRI ArcGIS Resources http://resources.arcgis.com/en/help/main/10.1/

The three primary types of datasets in GIS

Geodatabase can incorporate links to the non-spatial databases, shapefiles, images, etc. A key geodatabase concept is the dataset. It is the primary mechanism used to organize and use geographic information in ArcGIS. The geodatabase contains three primary dataset types:

  • Feature classes
  • Raster datasets
  • Tables

Creating a collection of these dataset types is the first step in designing and building a geodatabase. Users typically start by building a number of these fundamental dataset types. Then they add to or extend their geodatabases with more advanced capabilities (such as by adding topologies, networks, or subtypes) to model GIS behavior, maintain data integrity, and work with an important set of spatial relationships.

Geodatabase elements

All GIS users will work with three fundamental dataset types regardless of the system they use. They'll have a set of feature classes (much like a folder full of Esri shapefiles); they'll have a number of attribute tables (dBase files, Microsoft Access tables, Excel spreadsheets, DBMSs, and so forth); and most of the time, they'll also have a large set of imagery and raster datasets to work with.

Fundamentally, all geodatabases will contain this same kind of content. This collection of datasets can be thought of as the universal starting point for your GIS database design.

Importing KMZ/KML data into ArcMap and creating shapefile

Very often your collaborators/scouts send you their geographical data (points, lines, polygons) in KMZ/KML format as GoogleEarth application is freeware and readily available. In order to do GIS analysis on such data and incorporate them into your ArcMap project you will need to import such data into ArcMap.

1. Make sure you received KML and not KMZ (zipped KML package) data. If you received KMZ, open the file in Google Earth first and save as KML. Refer to this blog post for detail instructions. Note: You might try to work on KMZ directly in ArcMap, I confirmed that ArcMap 10.2 can import point data from KMZ file, but previous version and other data (lines, polygons) had given me problems in the past when I tried importing from KMZ directly.

2. Start ArcMap (new project or any project covering the area your data are coming from). Open ArcToolBox (click on the red toolbox icon on the top). In Conversion Tool/From KML start KML To Layer.

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Getting started with 2D resistivity interpretation using RES2DINV

Presentation, embedded below was developed to bring users up to speed in interpretation of their resistivity data. Class for end users was conducted in Indonesia and included training on field data collection with SibER-48 using ~ 900 m long profile in Wenner-Schlumberger and pole-dipole (remote electrode) 2D tomography. On the second day users received hands-on instructions on data import into RES2DINV software, quality assurance of the data based on visual approach as well as through RMS of the interpretation model. 

General discussion about non-uniquness of the subsurface interpretation modl for 1D, 2D, and 3D representations has followed this class. 

Slides can be viewed on http://www.slideshare.net/LarisaGolovko/training-on-res2dinv-and-siber48

Simple manual for geo-referencing several locations with Google Earth

1. Install Google Earth from http://earth.google.com . Open Google Earth and go to Tools\Options

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Location

Denver, CO

Setting K coefficient in LandMapper memory

LandMapper ERM-02

LandMapper ERM-02 is usually supplied with one four-electrode probe in Wenner configuration (optional) and the probe-specific coefficient K is preset in the device memory (K1). If you ordered or build multiple probes/cable arrays, you can change K1-K9 coefficients in the device. Note: K0=1 always and is not changeable by user!

  1. Press the power button to turn the device on. As the device is turned on the brief message "ASTRO-LANDVISER" is displayed on the screen of the device.
  2. Press and hold the FUNCTION key (►) and press the UP key (▲) to enter the coefficient changing mode.
  3. Scroll through K coefficients with the keys (▲) or (▼).  Change the value of the coefficient with the keys (◄) and (▲) or (▼). The digit to be changed is selected with the INPUT key (◄), the digit starts blinking and can be changed with the keys (▲) or (▼). The value of K0=01.00 is constant and cannot be changed by the user. If a measurement is taken using K0, the resulting output is resistance, not resistivity, and can be useful when the geometry of the array is constantly changing, as in 2D imaging or electrical tomography. In this case the resistance values can be multiplied by corresponding K coefficients according to the arrays used to obtain the resistivity. In conductivity mode, when measurements are taken with K0, the measured value is conductance, not conductivity, and the results can be converted to conductivity after measurements with appropriate geometrical coefficient.

Calibrate (calculate) K-coefficient for laboratory four-electrode cell

LandMapper with laboratory conductivity cellsLaboratory cells supplied by Landviser, LLC have been calibrated and the respective K-geometric coefficient is printed on the cell. The cells have to be filled to the top rim, in order for the coefficient to be accurate. Also, sometimes due to corrosion of conductive plates (electrodes) the coefficient of the cell might change slightly. Thus, you can verify K-coefficient of any cell, just follow instructions below.

For other tips, download Measuring Properties of Natural Systems with LandMapper ERM-02 (manual)

Location

USDA-ARS Washington D.C., MD 38° 53' 42.4032" N, 77° 2' 10.9176" W

LandMapper ERM-02: handheld meter for near-surface electrical geophysical surveys (FastTIMES December 2010)

was published in December, 2010 issue of FastTIMES, online peer-reviewed journal of EEGS. To cite this publication use:FastTIMES dec 2010 Agriculture: A budding field in Geophysics

Golovko, Larisa, Anatoly Pozdnyakov, and Antonina Pozdnyakova. “LandMapper ERM-02: Handheld Meter for Near-Surface Electrical Geophysical Surveys.” FastTIMES (EEGS) 15, no. 4 - Agriculture: A Budding Field in Geophysics (December 2010): 85–93. http://www.landviser.net/webfm_send/69

Registered users can download PDF of full text of proceedings paper from our website. Or browse online version below and leave your comments. You might also like to go to EEGS website to get PDFs of other publications on applications of geophysics to near-surface environmental problems published in this popular FREE online scientific magazine.

Abstract

On-the-go sensors, designed to measure soil electrical resistivity (ER) or electrical conductivity (EC) are vital for faster non-destructive soil mapping in precision agriculture, civil and environmental engineering, archaeology and other near-surface applications. Compared with electromagnetic methods and ground penetrating radar, methods of EC/ER measured with direct current and four-electrode probe have fewer limitations and were successfully applied on clayish and saline soils as well as on highly resistive sandy soils, such as Alfisols and Spodosols. However, commercially available contact devices, which utilize a four-electrode principle, are bulky, very expensive, and can be used only on fallow fields. Multi-electrode ER-imaging systems applied in deep geophysical explorations are heavy, cumbersome and their use is usually cost-prohibited in many near-surface applications, such as forestry, archaeology, environmental site assessment and cleanup, and in agricultural surveys on farms growing perennial horticultural crops, vegetables, or turf-grass. In such applications there is a need for accurate, portable, low-cost device to quickly check resistivity of the ground on-a-spot, especially on the sites non-accessible with heavy machinery.

Location

Laramie, WY 41° 18' 40.9212" N, 105° 35' 27.9636" W
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