Monday, February 18, 2008

Basics of ArcView GIS 3.x Graphical User Interface (GUI) PART I FREE!!



CLICK PLAY button above

Requirements
ArcView GIS 3.x (visit Room 027 in your spare time for access)
Adobe Flash Player 9 or higher, get it: DOWNLOAD
Knowledge of Windows: XP /Vista (we will try to help you folks with more on the basics in class)
Compatible sound card: with speakers for audio.

Geographic Information System (GIS) is a system of applications (software), hardware, data, human knowledge and qualified personnel to present information through analysis (data analysis) and manipulation of data linked to spatial (geographic) location.

I have developed the above definition based on experience, literature and skills I have acquired over the years both in field and outside the GIS conventional field. Even today I cannot claim to have reached the ultimate definition of GIS since more complex technologies and advancement are being developed every day. The human knowledge component has proved to be an integral part of the GIS process, since being a GIS guru alone using software cannot guarantee optimal results. We will discuss more of these interesting debates in class if we have to, but for now enjoy my first FREE online video GIS tutorial.

This series: Basics of ArcView GIS 3.x Graphical User Interface (GUI) is part of my interests in developing Multimedia GIS Projects (MGP) in the field of what I call the multimedia GIS era. I have already shared insights with some students in class (ENV 456, ENV 216) with modern examples as used in news channels like CNN and the BBC, and how Multimedia GIS is shaping and guiding the future of GIS concepts. In addition read more on the development and the future of Google Earth from Google Inc
As a kind gesture to my students & Staff within the Department of Environmental Science –University of Botswana (UB) the first part of this series is FREE of CHARGE to quickly assist and enhance the learning GIS experience application in the next series of Labs this semester. As time and resources permits will continue to provide these tutorials FREE online.

If your internet connection is slow you might have to wait a few seconds to allow buffering. I suggest you pause playback during buffering. From my experience try accessing early morning or late afternoon to night in UB since connection seems to faster during this period otherwise try private connections/home/internet cafes if you can.

In future I might make a secure download link.
Tested and works

THANK YOU

O.G.S.O

Friday, February 15, 2008

Guest Speaker: Blue Ridge Mountains Rotary Club: Rotary Club International


ENV 463:Determination of CaCO3 in water samples

"We will go through some basic concepts in the Lab , in the meantime please read through this weeks lab".. O.G.S.O

Introduction

Total hardness is defined as the sum total of the calcium and magnesium concentrations, both expressed as calcium carbonate in milligrams per litre. Originally, water hardness was understood to be a measure of the capacity of water to precipitate soap. Soap is precipitated chiefly by the calcium and magnesium ions present. Other polyvalent cations also may precipitate soap, but they often are in complex forms, frequently with organic constituents, and their role in water hardness may be minimal and difficult to define. When hardness numerically is greater than the sum of carbonate and bicarbonate alkalinity, that amount of hardness is equivalent to the total alkalinity called carbonate hardness. The amount of hardness in excess of this is called noncarbonate hardness. Hardness in water may range from zero to hundreds of milligrams per litre, depending on the source and treatment to which the water has been subjected.

Two methods could be used to determine hardness in water; hardness by calculation and the ethyenediaminotetraacetic acid disodium salt (EDTA) titration technique. We will be using the EDTA titrimetric method. This method is applicable to drinking, surface and saline waters, domestic and industrial waste waters. It is also suitable for all concentration ranges of hardness; however, in order to avoid large titration volumes, use a sample aliquot containing not more than 25 mg CaCO3. in this method, heavy metals are the main interference, causing fading of indistinct endpoints or stoichiometric consumption of EDTA. Suspended or colloidal organic matter may also interfere with the endpoint (in your report, explain how this inmterference could be overcome). In samples with low temperatures, colour changes become very slow while in hot samples; indicator decomposition could be a problem. A limit of 5 minutes set foe the duration of titration to minimize the tendency toward CaCO3 precipitation is advised. Titration should also be conducted at or near normal room temperature.

Apparatus and materials

Glassware – 25ml or 50 ml burettes
Volumetric pipettes
Graduated cylinders 100 ml Erlenmeyer flasks 250 ml
Volumetric flasks

Reagents

1. Buffer solutions; disodium salt of EDTA, magnesium sulphate heptahydrate, ammonium chloride, and ammonium hydroxide. (Na2EDTA + MgSO4.7H2O + NH4Cl + NH4OH)
2. Erichrome black T indicator
3. EDTA Titrant 0.02 N
4. Calcium carbonate standard solution 1 ml = 1 mg CaCO3
5. Hydrochloric acid solution 1 + 1
6. Methyl red indicator
7. Ammonium hydroxide (NH4OH ) 3 N

Procedure

Standardization of EDTA titrant with CaCO3 standard solution

1. Pipette 10 ml CaCO3 standard solution into 100 ml Erlenmeyer flask
2. add 50 ml of distilled water
3. Using a pipette, add 1 ml buffer solution and a small scoop of Eriochrome black T indicator. Mix well. Solution should be wine red.
4. Rinse the burette three times with the EDTA titrant
5. Fill burette with the EDTA titrant
6. Remove any air bubbles from the burette and bring level of titrant to 0.00 ml
7. Titrate the content of the Erlenmeyer flask with EDTA solution until the red tint disappears. The colour will turn purple. A few drops of EDTA at 3 – 5 seconds intervals will turn the mixture into a blue colour. This is the endpoint. Record the volume of EDTA used.
8. Perform this titrant check two more times.
9. Calculate the normality of the EDTA as follows

M1 V1 = M2 V2
Where M1 = Concentration of CaCO3
M2 = Concentration of EDTA
V1 = volume of CaCO3 used
V2 = volume of EDTA used
Titrimetric procedure

1. Measure 25 ml sample into a 250 ml Erlenmeyer flask and add about 50 ml of distilled water
2. Measure about 60 mL of distilled water into another 250 mL Erlenmeyer flask (Blank)
3. Using a pipette, add 1 ml buffer solution and a small scoop of Eriochrome black T indicator. Mix well. Solution becomes red.
4. Remove any air bubbles from the burette and check 0.00 level.
5. Titrate sample with the standardized EDTA until the red tint disappears. Continue titration slowly until the solution turns blue. This is the endpoint. Record the volume of EDTA used.

6. Calculation

Mg/L Hardness as CaCO3 = (V –B) x N x 50 x 1000/SV

Where V = volume of titrant used for sample (mL)
B = volume of titrant used for blank (mL)
N = the determined normality of EDTA titrant
50 = equivalent weight of CaCO3
SV = sample volume used use appropriate dilution factor if necessary