Lab Materials: Your TA will provide topographic paper maps 093G15. PLEASE DO NOT mark or draw on these maps.
Note that this lab includes 5 questions worth 5%: please email your answers to your TA your lab session next week. The questions are identified by number (1-5) and start in section 6; the lab also includes other queries to help you learn the materials.
- Canadian National Topographic System (NTS)
- NTS Map sheet for BC
- British Columbia TRIM
- Coordinate Systems and UTM Zones
- Paper Map Digital Scans
- Map Calculations
- Determining Map Sheet Names
- Digital Selection of Map Sheets
1. Canadian National Topographic System (NTS)
- Login to local machine and start the terminal server.
- Create a directory for today’s lab under your geog205 folder in Linux and call it topo_map
Canada’s national topographic map series uses the scales 1:1,000,000, 1:250,000 and 1:50,000.
In this section, you will explore the map numbering conventions for the National Topographic System 1:50,000 and 1:250,000 maps and how their numbering convention is based on the1:1,000,000 map series.
You have just seen Canada’s National Topographic System (NTS) for south of 68N. The1:250,000 NTS grid is 2 x 1 degrees and the1:50,000 NTS grid is 30’ x 15’
|Click to enlarge thumbnail at left. This far north note how narrow the widths of the map sheets have become compared to the lengths.The northern parallel of latitude of sheet 56 is 68 North Latitude. Note on the grid sheet to the north – sheet 57, the width of the 1:50,000 sheets have doubled to one degree of Longitude.|
|Click to enlarge thumbnail at left.The northern parallel of grid sheet 59 is 80 north Latitude. North of 80, the width of the 1:50,000 map sheets doubles again, to 2 degrees of Longitude. The primary grid also doubles in width creating a 16 Longitude x 4 degree Latitude grid.|
Full national index is at http://www.maptown.com/topographicalmaps.html
Detailed information on the topo series at:
2. NTS Map sheets for BC
Next, you will examine Canada’s NTS map sheets for BC in ArcMap
- Open your mybc.mxd from intro_gis lab as follows:
- File –> Open K:\geog205\intro_gis\mybc.mxd
- Remove checkmarks in the Table of Contents (TOC) to draw only: Rivers, Lakes, Transportation, Towns, Cities, BC
In the Standard Toolbar (shown below) locate the Add Data button:
- Click the Add Data button, and add the following layers from L:\labs\geog205\topo_map
Note the difference between file-> open (for a .mxd file – a whole map) and adding data (add data button to load data layers)
- Zoom to the Full Extent of the map. Save your map
- In the Table of Contents, place a checkmark to draw one_million_map_grid.
Note: where only a small portion of BC is within a map sheet, the edge of that map sheet has been cut down in size for this exercise. Examine the map, including the 1:1,000,000 grid and the grid’s map numbers.
- Draw a Zoom In box around the 1,000,000 scale map sheet 093.
- In the Table of Contents, place a drawing checkmark beside (turn the layer on) 250000_map_grid
Remove the label from the one million scale map grid as follows:
- In the Table of Contents, right-click one million scale map grid layer and remove checkmark beside Label Features – you did this in reverse last lab (properties label tab check off the label radio button).
- If not already on, turn the labels on for 250000 scale map grid: Right-click the layer 250000 scale map grid; and place a checkmark beside Label Features -what was set up in the lyr file so that the proper labelling occurred? Pan around to examine the map sheets across BC. Pan back to 093.
- Locate and Zoom In on 093G, and turn off the Label Features for the quarter million scale (1:250,000) layer:
You can make your map look similar to the image above by also adding the pgbound layer (shape files) in the topo_map folder – along with water layers in the n093g folder (under the topo_map folder).
- In the Table of Contents, place a checkmark beside 50,000 scale map grid and turn on its Label Features
Visually scan the map and note the 1:50,000 scale map numbers for 093G.
- Toggle the 1:50,000 layer on and off by removing/adding its drawing checkmark in the Table of Contents.
- Save your Map Document
3. British Columbia TRIM
BC provincial data are produced at 1:20,000 scale. The map sheets for TRIM (Terrain Resource Information Management) are also based on the 1:250,000 map grid. Each sheet of the entire 2 x 1 degree grid that covers British Columbia is divided into a 12 minutes of Longitude x 6 minutes of Latitude grid. This creates 100 TRIM map sheets per 1:250,000 map sheet.
|The TRIM sheets are numbered from 1 to 100. These numbers are appended to the 1:250,000 sheet name. British Columbia is covered by 7,027 1:20,000 TRIM map sheets. Click thumbnail at left to see the division of 093G into one hundred TRIM map sheets. Locate TRIM map sheet 093G.025 above. What is the number of the TRIM map sheet immediately above 093G.025?|
- Returning to ArcMap: In the Table of Contents, remove the checkmarks for the 1:50,000 and 1 million layers.
- Add data from L:\labs\geog205\topo_map\TRIM_20000_map_grid.lyr to ArcMap.
Ensure the 1:250,000 and the 1:20,000 map grid layers have drawing checkmarks.
- Turn labels on for the TRIM_20000_map_grid, and turn labels off for the 250000 scale map grid.
Examine the 1:20,000 map name system and explore the map.
- Toggle 1:20,000 on and off to see the division of each 1:250,000 map sheet into 100 TRIM sheets.
Other Provincial Topographic Data Sets: Alberta Map Names
Map Name Conventions and Scale – Don’t Let the Name Fool You:
At what scale would the data for grid map 093G7 be produced ? As 093G7 does not follow any of the naming conventions we have seen thus far (NTS or BC TRIM), there is no way of knowing what data set or scale of data is referenced. If the naming conventions were correctly written, then 093G07 is 1:50,000 NTS and 093G007 is BC Trim 1:20,000 data. Note the two digits for the sixteen 1:50,000 sheets, and the three digits for the 100 TRIM sheets. TRIM map sheet numbers are also written as 093G.007 using a period before the sheet number.
To add to the mix: You may still find 1:50,000 scale paper maps from the NTS system in east and west sheets. For example, 093G16E and 093G16W were printed at a time when they split the 1:50,000 sheets into E and W halves. This map sheet was possibly never updated.
4. Scale and Digital Maps
Canada’s national topographic map scales are 1:50,000 and 1:250,000. BC’s topographic map scale is 1:20,000.
Examine the spatial data at different production scales together in one Map Document in Arcmap:
- In ArcMap: File –> Open L:\labs\geog205\topo_map\mapscales.mxd (just click No to Save Changes when prompted).
- Then save this map file as you have done before: File->Save As (to your local folder as mymapscales.mxd).
The red rectangle Extent is the same extent as the figure above.
- In the Table of Contents (TOC), right-click the Extent layer, and Zoom to Layer.
- Draw all four layers at the same time. What is the display scale (check ArcMap’s scale readout)?
Experiment by turning off and on different layers to examine the generalization and detail between the different data scales.
- right-click the 1:20,000 Features layer in the TOC – click Zoom to Layer.
By adding and removing the checkmarks in the TOC:
- Turn on just the NTS 1:250,000 Features layer. Then turn on just the TRIM Features 1:20,000 layer. Switch between drawing each one.
Note: the entire 100 sheets of TRIM for 093G have been assembled for this exercise.
Note the visual clutter of viewing 1:20,000 (large scale data) for a large area.
Experiment with changing the display scale readout in ArcMap for TRIM and Pan around the map. Roughly, at which display scale are you able to clearly see the rivers of the TRIM data?
Modify the visibility checkmarks in the TOC so that only the 1:1,000,000 scale layer is displayed.
- Right-click the 1:1,000,000 layer in the TOC and select Zoom to Layer.
Q: What is the display scale in Arcmap’s scale readout? Can you see all the detail of the 1:1,000,000 scale rivers and lakes?
- Change Arcmap’s scale readout to read 1:1,000,000 (highlight the scale value, type in 1000000 – tap the enter key).
Display scale and data capture scale are now the same. As a result, a paper plot of a 1:1,000,000 map held up beside the monitor would show features at the same size. Is it easier to see the detail of the rivers and lakes?
- Add the map grids in order to see the boundaries of different feature data sets:
Next, you will examine digital vector map sheets. You are about to open a series of map documents. To open a new map use File – Open, you do not have to close the previous map as the software does it for you.
In ArcMap, examine each of the following map documents in turn:
- File – Open L:\labs\geog205\topo_map\n093\093_one_million.mxd. Say Yes to save changes.
Zoom In & Pan around the map at various display scales. Turn layers on and off. Zoom to Full Extent. Measure the distance across the entire map sheet. What is this value in kilometres (remember what you did last week with the measure tool – do you remember how to set the distance units).
- File – Open L:\labs\geog205\topo_map\n093g\093G.mxd
- Zoom to Full Extent of the map and measure the distance across the map sheet.
Q: What is this value in kilometres?
- File – Open L:\labs\geog205\topo_map\n093g15\093G15.mxd
Zoom In, Pan around and explore the features of this NTDB 1:50,000 digital map. Turn layers on and off. An advantage of the digital layers (vector data) is that you can turn the layers on and off, creating more or less detail within the limits of the data scale. You may also quickly change the symbology of digital data.
It is challenging to visually scan the details of a digital map compared to a paper map. However, if the attributes of the digital map are up to date, you can digitally search for some features. Try this digital search for Haggith Lake:
- Click the Find tool . Click on the Features tab. Type in Haggith Lake in the Find field.
- Click the Find button. A record for Haggith Lake should appear in the Find Window.
- Right-click the Haggith Lake record and select Zoom To. You have zoomed in on Haggith Lake, but perhaps too close. Change the display scale to 30,000.
- double click on the Haggith Lake record to see how ArcMap indicates the lake’s location
Information about the Map – ‘Metadata’
On the printed maps, the edge of the NTS paper map contained the following information:
How current is this dataset? What is the map’s coordinate projection and datum? What was the data capture scale? What is the map’s name? What is the NTS Map Sheet number?
The NTS paper map contained this valuable information on the edge of the map.
Where is this information for the NTDB data? Digital metadata for NTDB are located on the Geogratis website, and in a digital file. You need not examine these data, but appreciate that much of the information on a NTS paper map is stored in a file format in separate locations to the vectors, and is not available at a glance.
To see an example of a portion of NTDB metadata:
- In the Table of Contents, right-click rivers and from the subsequent context menu, select Data –>View Item Description.
Is this information as easy to read as the edge of the paper map sheets?
- Examine vector layers for TRIM data:
- Open the Map Document for BC TRIM 1:20,000 data: L:\labs\geog205\topo_map\trim93G\trim_093G096.mxd
- Now change the coordinates display to remove the decimals in the coordinates. Click Customize ->ArcMap Options->Data View
- In Coordinate Display In Status Bar box, change Round coordinates to: 0 decimals.
- Click Apply, click OK.
- Zoom In, Pan, turn layers on and off. Explore the map.
At any given scale, the development of map line work involves simplification. In the example below, compare the photograph to the map and note the simplification.
Comparison of image with 1:50,000 map vectors
Next, compare the image and the vectors shown above in 093G15.mxd as follows: re-open 093G15.mxd by clicking File and selecting the map document from the history list at the bottom of the pull-down menu.
- Next, add the image from the illustration: Add Data L:\labs\geog205\topo_map\ikonos_02.ecw
- At top of the Table of Contents, right-click the top entry of the table of contents - labeled NTDB 093G15 and select Turn all Layers Off
- Scroll to the bottom of the Table of Contents and click on the ikonos image, then right-click ikonos_02 and select Zoom to Layer
Place a drawing check mark for ikonos_02, and examine the image. Note the detail. A display scale between 1:10,000 and 1:30,000 is appropriate for this step. Pan around the image and note the detail of the area. This (satellite) image was captured in 2002.
The map’s vector layer features are current to 1980, with an update for cultural features in 1985 and an update for roads in 1996. New cultural features, e.g. new buildings and developments after 1986 and new roads after 1996 do not appear in the vector NTDB map layers.
Turn on layers one at a time to note two things: the simplification of the vector layers compared to the features on the image. You may also find features missing in the vector layers, but which are in the image, e.g. new roads.
Comparison of image with TRIM data
- Re-open the TRIM Map Document: Main Menu – File – Open, and select from the bottom of the pull-down menu: L:\labs\geog205\topo_map\trim93G\093G096_TRIM.mxd. Say NO to Save changes.
- Add Data: L:\labs\geog205\topo_map\ikonos_02.ecw
Examine the level of simplification of features for this TRIM 1:20,000 map.
6. Coordinate Systems & UTM Zones
|Note the markings at the edge of this 1:250,000 map sheet. The Graticule around the map is labelled with Longitude and Latitude values, illustrated with black and white bars (circled in the illustration at left). At this scale, these bars represent 5 minutes.|
|Note the pale blue grid lines at four centimetre intervals across the paper map. This is the measured grid. At a scale of 1:250,000 four centimetres represents 10,000 metres (10 km) in the real world. Near the four map corners of the map are label values. In the example at left, the intersection of the blue lines is marked by the red dot. The x,y coordinate for this dot is:560000, 5980000 as shown by the blue labels.These values are in metres. X values, known as Eastings, increase from left to right (increase in the easterly direction).Y values, known as Northings, increase from the bottom to the top of the map (increase in a northerly direction).|
The notes above also apply to the 1:50,000 paper map, except that the Graticule and measured grid intervals are different. The Graticule interval for 1:50,000 NTS paper map sheets is one minute, and the measured grid interval is 1,000 metres.
The paper distance across a blue measured grid square is 2 cm. On a 1:50,000 scale map, 500 metres is represented by one cm, or half the width of the blue measured grid square. One hundred metres are represented by 2 mm on a ruler.
Reading UTM values from printed maps
Collect a copy of the 93G15 map sheet: PLEASE DO NOT MARK THESE MAPS – KEEP PENS AWAY FROM THEM!
The South tip of Tabor Lake (east portion of map) has these UTM Coordinates: 529350E, 5972750N
Longitude and Latitude (LL) (to the nearest minute): 122 degrees 33′ W 53 degrees 54′
Question 1: What are the UTM and LL values for the junction of the entrance road into UNBC from University Way?
[ visually estimate to the nearest 15 seconds or 100 metres]
Question 2: What are the same values for the control tower at PG airport?
Now check these UTM and Geographic values using the PGMAP website: use the xy icon at bottom left (‘WKID’ stands for well-known ID !)
Digital Coordinate Readout
- Open the Map Document L:\labs\geog205\topo_map\n093G015\093G15.mxd
If necessary, zoom to the Full Extent of the map. Move your mouse slowly around the map. Notice the coordinate readout lower right corner of ArcMap window e.g. . This represents an x,y coordinate value of 519280, 5968971. Your values will be different as you will be at a different location on the map.
Notice the values change with the movement of the mouse. Zoom In on any feature of interest, and hold the mouse over that feature. The coordinate readout displays the location of the feature. These values are in metres.
To change the coordinate readout to Longitude and Latitude:
- Right-click the Data Frame (the map itself) and select Properties from the menu.
- Click on the General tab. Change the Display Units to Degrees Minutes and Seconds as shown below..
- Click Apply, click OK.
Now the coordinate readout should be Longitude and Latitude as you move your mouse. This display of coordinate values does not affect the underlying data.
- Zoom to Full Extent.
You can also search for a coordinate location: change the coordinate display back to metres.
- Click the Go To XY button . Click the dropdown arrow, change units to metres:
- Type in the location X: 529000 and Y: 5973000. And tap the Enter key. You will see the location flash.
- Next, click the Go TO XY toolbar’s Zoom To button to zoom in on that coordinate location.
UTM Zones for BC and Map Layout
- Re-open mybc.mxd from last week (your intro_gis directory). Turn off all the map grid layers except 1:250,000 scale layer. Leave the topographic layers visible.
- Turn on the labels for the 1:250,000 layers as follows: right-click 1:250,000 layer – Label Features.
- Zoom to Full Extent.
- Click Main Menu –> View -> Layout View. You are now looking at your map of BC on a page layout.
Next, adjust the label size as follows:
- In the Table of Contents, right-click British Columbia Data Frame and click Properties.
- Select the General tab, change the Reference Scale to 3,000,000 (highlight the number, type in 3000000 – no commas – tap the enter key). OK.
Next you will add the Graticule defining the 6 degrees wide UTM zones that cover BC.
- Right-click the British Columbia Data Frame –> Properties –>Grids Tab.
- Click the New Grid button –> select the Graticule as the type you want.
- Click Next. Modify the intervals as shown here:
- Click Next, Next, Finish, OK.
VERY IMPORTANT: When working in ArcMap’s Layout View, the software is slower. Wait until the spinning earth globe at the bottom of the software window finishes. If you don’t, you will probably freeze the software. If BC does not fill the layout:
- Click the Full Extent button and then zoom in around BC with the Tools toolbar Zoom In button.
- Save your work: File – Save You can also click the save icon . Float your mouse over this button, and note the pop-up: you can also save your changes to a map document by using the keyboard keys CTRL and S at the same time.
Since you are on the Layout Page, you now have a Layout Toolbar
These buttons allow you to navigate the page. Use the Layout Zoom In and Layout Pan tool to examine the lines of Longitude that in this case represent the UTM zone boundaries. Zoom to the full page at any time with the Layout Zoom Full Page button.
- Save this map document as a new Map Document name as follows:
- File – Save As K:\geog205\topo_map\utm_zones_bc.mxd
Next, you are going to label the UTM zones. Add the following layer:
- Add Data L:\labs\geog205\Topo_map\map_sheets\utm_zone_labels_bc.lyr
Note the labels from Zone 7 to Zone 11.
How to determine the UTM Zone for a map sheet:
TRIM sheets are numbered 1 to 100 and each is appended to the 1:250,000 sheet name, for example: 093K.007
Based on the quarter million sheet name, 093K, you can locate the UTM zone map for any TRIM sheet.
- Use the Layout Zoom In button to zoom in on northern BC. To find the UTM Zone for 093K.007:
- Click the Find button. Type in 093K.
- Click Find. Drag the Find window off to the side.
- Right-click the listing for 093K and select Flash.
You can see from the map that 093K will be found in UTM Zone 10. All TRIM sheets beginning with 093K also are in Zone 10.
In which UTM Zone will you find Tofino?
7. Paper Map Digital Scans
Switch back from layout view to data view: View-> Data View
- Start a blank map. File – New
- Add Data L:\labs\geog205\topo_map\n093G15\princegeorge.tif
You are examining a digital scan of the paper map.
- Zoom In and Pan around. Note the coordinate readout changes as you move the mouse. A digital scan of a paper map can be georeferenced (this is not always true).
- Zoom In on a corner of the map so that you can see the UTM label values. Hold your mouse over the intersection of the blue measured grid lines. The digital coordinate read-out lower-right on ArcMap should match these values.
You can turn the whole image on and off. There are no individual layers (e.g. you cannot turn off roads in this raster scan of a paper map).
If you query this scaned dataset, a single pixel flashes listing the colour values. No map attributes are attached. You cannot change the symbols. Use the Identify tool to click on the raster – note the cell values.
8. Map Calculations
In ArcMap, open the Map Document L:\labs\geog205\topo_map\trim93g\trim_ 093G096.mxd
Perform the following steps:
- Using the Go To XY tool, type in the x,y coordinate 508100, 5978400 and Zoom To location.
- Using the Identify button, click on the contour beside the lake. The value is in metres above sea level and represents elevation. Click the next closest contour. Note its value. The difference between these values represents the contour interval (change in elevation between successive contours).
- Select the Identify button
- Click on the lake
- The area is given in square metres
- Convert the area to square kilometres (remember it is an area measure – 1km = 1000m, 1 km sq = 1,000,000 sq m)
- Convert the area to hectares (1 ha = 100 x 100 m = 10,000 sq m)
Question 3a: what is the contour interval for this TRIM data ?
Question 3b: what is the area of the lake in hectares ?
9. Determining Map Sheet Names and Numbers
Most people do not want to have to memorize the map sheet they require for reference or data downloads. You can use the GeoBase WMS layer mentioned above for a reference layer. You can also try to find web mapping sites to use as a reference site.
There are not many sites that have the NTS grid as a webmap layer, but there is a web-based dataset containing NTS map names for BC, developed by the British Columbia Geological Survey (BCGS), known as MapPlace
from this website, launch MapPlace 2
(MapPlace 1 required an extra application available only with Internet Explorer).
BC has used the global OpenStreetMap to display BC data, so the coordinates are not local.
Under Legend, Tick on Base maps, expand Map Grid, and tick 1:20k mapsheets and mapsheets (labels) and UTM Zones
The UTM zones are just on BC – they represent an attempt to overlay a rectangular coordinate system on a curved earth
Now zoom into the PG area
Under ‘Legend’ add (tick) Provincial Parks (under Administrative Boundaries)
To see the map labels, float your mouse over the portion of the maps, and the label appears
The closest provincial park to the NW of PG is Eskers
Question 4a: How many 1:20,000 map sheets are needed to cover the Eskers provincial park ?
Question 4b: Which map sheet (number) includes most of the city of Quesnel (south of PG by ~111km)
For all of Canada, not only BC, If you don’t know the NTS map-sheet where a particular place is located, you can find the answer using this web site – enter the name in the box and hit the ‘submit’ button:
Question 5: What are the federal map sheet(1:50 000 scale) numbers for Moose Jaw (Saskatchewan) and Dildo (Newfoundland) ?
Send your answers by email to your Lab TA (by your lab session next week).
- Click Start -> Logoff to logout from terminal server
- Click System->Quit->Logout from the top menu to logout from local machine.