Monday, January 31, 2011

Lab # 4 Digitizing in ArcGIS


Digitizing the Image of Iraq into ArcGIS was a very interesting process. Digitizing a country like Iraq allowed me to gain experience in digitizing points for the cities, polylines for the rivers, and polygons for the provinces.  In addition to the shapefiles that the lab asked me to make, I made a shapefile specifically for Baghdad, Iraq’s capital, in order to make it stand out and one for the international border, to highlight Iraq’s overall shape. Once I had everything digitized, I made the city names smaller and colored them green in order to distinguish them from the province names and colored the river names blue. 

After my experience with digitizing, I know why they say 99% perspiration, 1% inspiration. Digitizing was a unique experience because it was the first time we took data that wasn't formatted for ArcGIS and turned it into data that could be read and used in the program. There are many useful applications of digitizing and it will continue to be important so long as we continue to digitally map. 



Tuesday, January 25, 2011

Lab #3 Geocoding


The topic that I chose is a family wants to move to the city of Berkeley, California and is looking to live near a school (within 400 meters) and also (if possible) live walking distance (400 meters) from a famous Berkeley Bowl super market. The first step I took was downloading the Alameda county data from the US census website, then I cut out the Berkeley city limits and hid everything else.

To solve this problem I used Geocoding, which is the process of finding geographic coordinates from other geographic data I downloaded, from the street addresses of the schools to locate and label their locations in the city limits of Berkeley. Since there were only two Berkeley Bowls I manually found their streets on the map and made an educated guess of where they should be located. Once they were labeled I added a 400-meter buffer zone around each one to see if any neighborhoods were both 400 meters from a school and from a Berkeley Bowl. In the final result there were multiple neighborhoods that overlapped with both preferences. The schools that were located near the Berkeley Bowl west were Sunshine Pre-School and Ecole Bilingua de Berkeley and near the original Berkeley bowl were Longfellow Middle School, LeConte Elementary, and Malcolm X Elementary. Now the family can do research on theses schools to make their final decision.

Geocoding facilitated the narrowing down of the right neighborhoods to live in, and thus the solution to the problem. There are a lot of schools in Berkeley and as I experienced from the two Berkeley Bowls, manually locating the address of every school on a map would take a sufficient amount of energy and time. Geocoding allowed me to take information from an excel sheet and visualize it directly onto the GIS data of Berkeley that I had already uploaded onto the GIS software. The type of geocoding I used is called address interpolation. Since the GIS data already had the street network data, the geocoding matched with only some small problems appearing.

Although my topic only needed to be relatively accurate, one of the major barriers in geocoding is the lack of exact accuracy. Accuracy is extremely important when professionals use geocoding. An ambulance can’t only rely on geocoding because they may end up close to, but in the wrong place. As geocoding becomes increasingly more important to business, the accuracy of the street data and geocoding will only improve and it will become ever more important.