Don’t buy land in this area !

Bank Erosion 2003 - 2010

Around the corner on the Mekong Side

1. Create a new shapefile in ArcCatalog and set the coordinate system. In this example, I have created a polygon shapefile called landuse_2012.shp

2. Add the feature class landuse_2012.shp to ArcMap and open the attribute table. Notice that it has no features.

3. Add a field called LU_CODE with type Short integer

4. Add a field called LU_TYPE with type Text and Length 35

5. Delete the field called ID that was added by ArcGIS.

6. In the Table of Contents, right click on the layer and choose Properties -> Symbology

7. Change the symbology to Categories and the Field to LU_TYPE

8. Click the Add Values button, then enter the description of the first class, e.g. Forest

9. Then click Add to List

10. Change the Symbol to the desired color e.g. Green

11. Then repeat the process, adding new classes called “Water” and “Farmland”, for example

12. Click Ok to close the layer properties

13. Zoom to the area where you are digitizing new features

14. Make the Editor Toolbar visible and choose Editor -> Start Editing

15. Notice that in the Create Features window, the three classes are displayed

16. Now click the Organize Templates button

17. Select Farmland and click Properties

18. Set the LU_CODE field to 3

19. Click Ok and repeat the process for Water (LU_CODE = 2) and Forest (LU_CODE = 1).

20. In the Create Features window, select Farmland and in the Construction Tools window, select Polygon

21. Now draw a farmland polygon as desired

22. Create a single feature for each class. You will need to change the class in the Create Features Window to switch classes.

23. Stop editing and open the attribute table.

24. Notice that all features are fully attributed.

Recent announcement from USGS:

OrbView-3 satellite images collected around the world between 2003 and 2007 by Orbital Imaging Corporation (now GeoEye) at up to one-meter resolution can now be downloaded at no cost through USGS EarthExplorer.

“This is a significant addition to the USGS archive and a valuable resource for the global science community,” said Matthew Larsen, Associate Director, Climate and Land Use Change. “Free access through the USGS archive amplifies the utility of the data, making it feasible for many researchers to study large areas at this level of accuracy.”

I took a quick peek at what is available for Cambodia (see graphic below). Would be nice to have more I suppose, but hey, better than nothing.

Orbview-3 Coverage Available for Cambodia

Here are the results of a short test of the satellite tracking by the Trimble R6 rover with GLONASS under forest canopy in Laos. At the time, we were tracking about 4-5 of the GPS satellites exmitting L2C signals, which better tracking performance than regular L2 under adverse conditions.

Forest Site with Undergrowth Cleared

Site 1 - Relatively Open - PDOP 1.6

Site 2 - Open Canopy - PDOP 1.6

Site 3 - Closed Canopy - PDOP 3.4 - Not bad !

Skyplot from Trimble Planning Utility for same time.

I initially got pretty excited by this discovery on http://earthexplorer.usgs.gov/ as some of the imagery is 2-4 ft in resolution and dates from the mid-60′s to mid-70′s. It was de-classified in two batches; 1996 and 2002. However, it seems that most of the imagery is quite cloudy (coincidence ?) and there is not much of the 2-4 ft stuff. Additional frustrations are that is costs money (alebeit a small amount – around $30) and cannot be downloaded. But anyone determined enough should be able to their hands on this.

I’m sure there a much larger collections that are not yet de-classified, covering the entire Khmer Rouge period in Cambodia. I wonder why.

Sceenshot of Black and white KH-7 High Resolution Surveillance Photo North of Phnom Penh. Image Date: 1967/05/24. Camera Resolution: 2 to 4 feet

Screen shot of image covering parts of Kampong Thom and Kampong Cham. Acquisition Date: 17-JAN-76. Camera Resolution: 20 to 30 feet.

Camko City Satellite Time Series

This time series of Satellite images in Google Earth show the development of Camko City on what was once Boeung Pong Peay. The site lies on the northern edge of Phnom Penh city and is slated for completion in 2018.

You can explore the recent history of Phnom Penh via satellite imagery using the button in Google Earth.

You may not know it, but if you are in Phnom Penh, you may be sitting below river level RIGHT NOW ! Of course, the level is subsiding and 1.55m below flood level so the risk is very low. The map below shows the water level around the independence monument if flood defenses were breached.

For more information about this map, please feel free to Contact Us

Flood Risk near Independence Monument, Phnom Penh

Here is an interesting comparison in the change of land use in Pailin in western Cambodia over the last 20 years.

Landsat Image from 2001 (30m resolution)

Below is an image from 2011, taken by the RapidEye satellite. Nearly all forested areas have been converted to agriculture, except the minefield along the Cambodian-Thai border on the left of the image. Dark patches indicate remaining forest.

RapidEye Satellite Image (5m resolution) from 2011

I drove past this sign on National Road Number 2, which details the plans for Boeung Tumpun, including construction of new roads, canals and reduction in the lake area.

Boeung Tumpun Development Sign, NR2

Based on this sign, I’ve drawn up a rough sketch of the boundaries, which can be viewed in the context of the current ground situation in Google Maps: http://maps.google.com/maps/ms?msid=205681469191653522990.0004a8dd06976a6aab585&msa=0&ll=11.511313,104.928017&spn=0.047519,0.084543

Boeung Tumpun Development Map

1. Go to Start  >  Run, then  type “regedit”

2. Under Registry on the left hand side go to My Computer\HKEY_CURRENT_USER\Software\ESRI\Desktop 10.0″

3. Right click on “Desktop 10.0″ add new key “Common”

3 Right click on “Common” add new key “CodePage”

4 On Codepage key add new string value “dbfDefault”

5 Right click on string value “dbfDefault” modify it value field to “UTF-8″

Editing the Registry

6. Reopen Arcgis and then try to edit attribute table by typing Khmer character.

Khmer Unicode Map Labels