When you receive a referral or your forestry dept gives you a scanned map. You start by scanning the map and saving it a a jpg. JPG is a file extension, it is called JPEG, short for JOINT PHOTOGRAPHIC EXPERTS GROUP.
The next step is creating a folder using ArcCatalog; and in your folder create two (2) folders 1. Shapefiles 1. Images
Still using ArcCatalog, copy the scanned copy of your new map into your new images folder.
If you don't have the shapefiles for the map, you have to download it from the NRCAN data site, which contains the index of CANVEC shapefiles. After you download the files you have to extract and unzip the files. Copy your files into your new shapefile folder. Using ArcCatalog you can convert the code so you can recognize the files, for example: 09k11_3_0_BS_2010009_0 change this to roads.
After you are done converting the codes. Using ArcMap; click add data +, then add all your shapefiles you need: waterbodies, rivers, streams and roads. Right-click each layer properties and categorize each layer with right symbols and color.
Next step is to locate and find the coordinates on the map image using Lats/Long and pick four points; which will make a rectangle : : North, East, South, West and depending on your map, you may have to convert the units.
On your main tool bar select X-Y icon; and your x-y tool will pop on your screen. There is a small down arrow key, this is where you change your units from Decimal Degrees to Degrees Minutes Seconds or vis-a-versa.
Type in your lats/longs for example: NW Lats: 54o 124' 0" Long: -124o 24' 0"
If it is in degrees minutes seconds; you can convert it to decimnel degrees for example: NW 53o 59' 0" = 53 + 59/60 = 53.98
When you are done converting your coordinates; go to View -> Toolbars ->georeferencing. On your georeferencing toolbar select the X-X (green x-red x), then you can add your coordinates as: add point, from your digital map image to your shapefiles.
Continue this process until all four (4) coordinates are in place, you can see the map image moving to the coordinate points.
This links the image to your shapefiles, after you are done; click the down arrow on the georeferencing toolbar and click Fit to Display, this fit to screen the four points.
On your georeferencing toolbar there is a box call View Link Table, when you click on this, a Link Table will pop out. This table contains: link, your x y source and x y map and Residual (columns and rows). This also shows how much error or Total RMS Error between the map and image.
If you have a large value of error, you would have to use your X-X tool and zoom to a river, stream or landmark which is visible to the nake eye and link from the image to the digital file, at least do 4 links, the check your RMS error and if you have large residual value; you can delete them.
When you are satified with your map, click the georeferencing tool and select Update Georeferencing.
Save your map; and anytime you would need the referral you can bring it up from your computer.
Create new shapefile
Next step is to to View -> Toolbars -> Editor and on your Editor toolbar click on Start Editing and click on the pencil icon (aka Sketch Pencil) and start outlining the area which the referral is based on for example a cutblock area. Zoom to your map and start clicking with your pencil icon on the outline of the area, and when you are finished, right click and click on Finish Sketch.
Save your referral shapefile and is ready to be viewed at any time.
Subscribe to:
Post Comments (Atom)
This is a good list of steps. You may want to make some of it less specific e.g. getting CANVEC data. The user may have some other source. Simply indicate that the user must get data from a relevant source. Good effort.
ReplyDelete