Archive for January, 2011


Geo data base defenition

A Geo data base is the comon data storage and management framework for ArcGIS, it combines spatial data with data repositories to create a central data repository for spatial data storage and management. The geo data base is designed to store,query and manipulate geographic information and spatial data of a low dimensionality. Vector data can be stored as point, line or polygon data types, and may have an associated spatial refrence system. With in a GIS data base  spatial database is one component that can be used to store and manipulate data. Typically a complete system will also include client software to view and edit the data stored within the database.

Advanced editing

1.I ended up with 48 parcels.

2.I added three roads

3.Tara pl,rav court and Law ave

4.drawing tool,arc tool and circle tool or what ever its called, the circle one

1.A point feature

2.it is a polygon

3. the data could represent, points/places on a map or it could be the outline of a polygon

New Brunswick Map System

The official mapping system in New Brunswick is the Digital Topographic data Base or DTDB, it was adopted in 98 and it is a digital representation of natural and cultural feautres of NB. It is made up of two data bases one being the Digital Terrain Model Data Base and the Enhanced Topographic Base. The DTB contains features such as elevation mass points, check points, and spot heights. The ETB data base contains features such as buildings, designated Areas, delimiters, land cover, land features, transportation (road/railroad), structures, utilities and hydrography.

Here is a link to the information website for NB

http://www.snb.ca/gdam-igec/e/2900e_1c_i.asp

And here is a link which you can map a map with

http://geonb.snb.ca/geonb/

Roads

The best results came from digitizing at 1:5000 i think because i could view the entire image but was close enough to pay attention to the details.

The most difficult was the 20,000 because its hard to see what you are doing

Lakes

The best result i had was on 1:1000 scale on the lake because i was able to see the detail

the hardest was definately the 20000 as i could hardly see the lake contours

Cars

The scale impacted it alot because you cant see the cars very well once you zoom out so you have to use a point file instead becasue you cant see enough detail to make polygons

Yes i used polygons and points

It would be best to use large scale for making polygons , it would be best to use the mid scale for roads and the small scale just sucks for any detail so i wouldnt use it

I would use the large scale so i could be more detail oriented even if it took more time

The Things I noticed about the comparison between these two files are as follows

-The shapefiles have detailed and complete polygons and lines

-The DGN has a grid

-The DGN loads much faster then the shapefile

-The DGN is more basic however, the shapefile is easier to analyze

-When removing or adding layers to the shapefile it re-draws every time, where as the DGN it just appears or is removed

-The shape file has alot of complicating points

-Shape has alot more layers then DGN

-DGN has in complete features

-DGN has little to no values

my interesting map

This is a back roads map book map, it has all the off road trails on it, creeks, topography, lakes,hiking trails,ski trails etc. I have 3 back road map books i use to navigate the back roads. If i was in this area i would find this map very useful as well as all the other back road maps.

here is a link to another cool map i found indicating industrical traffic

http://www.for.gov.bc.ca/ftp/DPG/external/!publish/!web/09WebUpdate/2009_Chief_Lake_Hauling_Mailout.pdf

Map scale types

 large scale maps
There are two “classifications” of map scales, there are large scale maps and small scale maps. First of all there is a large scale map, a large scale map is a map that represents a more detailed area, this scale respresents the unit used on the map related to the actual unit of distance. There are many examples of maps that could be used as large scale,scale is important to me because i often use large sale maps to show me topographical details of an area, i need to know where i am and where im going so it is just easier to use a large scale map. Here are some examples of those maps and why they would be large scale.

Here is a large scale map of Prince George, you can see in the top right hand corner of the map, the unti of measurement, it appears about one inch is equal to 400 m on the map, this scale shows close detail to the small area and this map displays a small but detailed area of the city.

Here is a another large scale map, it looks to be about 4-5 cm = 500 m, this is a small scale because it shows a smaller area, the scale does not have to be a high number or a high unit such as km to represent the area as it is not large enough to need a small scale.

Here is anothe large  scale map example, it is a bit more zoomed out and more detailed then the other maps and does not have a scale on it but if it did it would be an amount such as 5 cm= 500 m.

small scale maps

A small scale map is a map with a larger scale such as 1:100,000 , which is 1 cm= 100,000 km. This scale would be used for larger maps such as a map of canada or even a map of north america, a small scale map is a map with a larger scale most likely with higher units, you could use a scale of 1cm= 10000000m but its easier to use the larger units for larger scale maps.

Here are some examples and explanations of small scale maps

This is a map or North America, it has a scale of 1:38,700.000 which is pretty large but it represents a large area which make the scale represent a different area. In the bottom left hand corner you can see the scale where you take measurements, it appears about 1 cm is equal to 300 km so if the map measure 4 cm from point a to point b it would be 1200km in reality.

This map may be hard to see, but I am assuming it would be a small scale as it covers a large area, so a small scale map covers a larger area thus it mus have higher units of measurement and a higher ratio in order to properly project information to the user.

In conclusion, it is quite simple to understand smaller scale maps have a larger ratio to cover smaller areas like P.G and small scale maps have a much higher ration to cover long distances such as Canada.

Vector

Pro’s

  • Data can be represented at original resolution without generalization( no resizing data)
  • Graphic output is usually more aesthetically pleasing (looks better for example it is less block like and gives better representation of the shape)
  • Most data is in vector format so there is no data conversion
  • allows for efficient coding of topology (for example proximity and network analysis )

 

Con’s

  • The location of each vertex needs to be stored explicitly
  • Algorithms for manipulative and analysis functions are complex and may be processing intensive. Often, this inherently limits the functionality for large data sets, e.g. a large number of features.
  • continuous data is not effectively represented for example elevations
  • Spatial analysis and filtering within polygons is impossible

 

Raster

Pro’s

  • The geographic location of each cell is implied by its position in the cell matrix.(for example bottom left corner)
  • Due to the nature of the data storage technique data analysis is usually easy to program and quick to perform.
  • The inherent nature of raster maps is ideally suited for mathematical modeling and quantitative analysis.(for example attribute maps)
  • Discrete data (such as forestry stands) is accommodated equally well as continuous data, (e.g. elevation data), and facilitates the integrating of the two data types
  • fixed resolution( can be good or bad)
  • “remembers” the start and end points of  a line

Con’s

  • cell sizes determines resolution at which data is represented
  • It is especially difficult to adequately represent linear features depending on the cell resolution.
  • Since most input data is in vector form, data must undergo vector-to-raster conversion. Besides increased processing requirements this may introduce data integrity concerns due to generalization and choice of inappropriate cell size.

Photo examples

vector image vs raster image

haiti disaster and GIS

In 2010 there was a large quake in Haiti which caused over whelming amounts of damage . GIS can be applied everywhere so my focus will be on how it was and will be used to reconstruct and rebuild as well as how it could have been used. GIS was  used in haiti to show the worst shock of the quake and where it was not felt at all. With this information not only can work and reconstruction crews be more efficient but so can everyone else such as health and safety workers, the GIS concept in problem solving of this disaster is very important. The following map was constructed by ESRI to aid in showing the quake magnatudes.


This map will aid in the reconstruction of haiti because it shows the worst damaged areas, this is a perfect example of how GIS will and is being used in the reconstruction because the agencies that are doing the rebuilding can use this map and can formulate a plan to either do the easy rebuilding first and work in or start where its worst and work there way out which is the most likely plan , by using this map they can be more efficient in clearing the rubble and rebuilding things.

Here is a second example of GIS in haiti, this map contains topography and streets, rivers etc. they could layer this map with the most damaged parts to show work crews how to access these areas. This map is also important because the damaged areas could be hard to navigate for people so the GIS map would be a great tool to help people find what ever point it is that they need to go to. This map always shows resources like ari ports etc

ESRI did alot of GIS work to help with haiti and there are many of examples of it. A GIS map could have been used and was most likely used to show shelters,hospitals,camps etc this map would be very useful ,for workers could also be made on current work sites

On january 15th Rescue crews rushed to the aid of haiti and ESRI provided free data to all agencies that were assisitng in the relief, this information would have bee crucial to those agencies to formulate quick strategies of rescue so in this case GIS could have very well helped save lifes. Once the quake hit data was being collected by satelites , the data was then processed into maps to show the destruction.

GIS map showing earth quake damage

This map was constructed with a satelite image to show the most damaged areas, if work crews even got close ups of this image they could view streets etc and use this information to station hospitals and rescue crews. This map would have likely been used to station crews as they can see everything they need to plan quickly and easily. Of course this map is only of the one area im sure  that there was many maps just like this one of all of the areas that different crews could obtain to rebuild.

The GIS concept in rebuilding is huge and possibly over looked all of these example maps are exactly what the rebuilding crews need to plot out where the worst rubble is, where they will put excess rubble, where they are building and things of the matter that concern them. There were most likely GIS specialists working around the clock to help relief and reconstruction workers.

So in conclusion , does GIS help with the reconstruction of Haiti? of course and probably more then most people would think. The GIS concept here is huge and helps every agency involved to solve problems quickly and efficiently and that can make a huge difference.

article;

Haiti disaster relief by ESRI22 January 2010
 
 
 
 
 
 
 

Redlands, California, US: ESRI is working closely with the GIS community and agencies responding to the Haiti earthquake by providing software, technical support, GIS data and personnel. In the immediate aftermath of the earthquake—characterised as one of the worst natural disasters ever in the Western Hemisphere—GIS- is assisting in identifying areas of extreme damage, impacts to critical infrastructure, areas suitable for food and water distribution and more. It gives officials critical decision making information.

Personnel and agencies whoever are helping the relief effort can take advantage of maps, data, software and Web services available online through the ESRI Web site (www.esri.com/haiti.) Some of the data and services include a 25-meter reference grid of Haiti, an ESRI Geo Viewer and Haiti basemap data from United Nations available on ArcGIS Online. In addition, ESRI-generated earthquake and recovery maps are available for both the media and public. ESRI will provide updates as they become available.

Russ Johnson, Director of Public Safety Solutions, ESRI, said, “Our job is to help where we can empower our users with better GIS support. As soon as we learned of the terrible event in Haiti, we activated our emergency operational procedures to assist emergency services, humanitarian relief, health professionals, NGOs [non-governmental organisations] and others. These organisations are working extremely hard to make a difference. We’re working to assist their efforts.”

 

 

Another excellent and interesting link on how GIS was used to help haiti relief; http://www.esri.com/news/arcnews/winter1011articles/providing-building.html