1 / 27

Tier 2 Training

Tier 2 Training. Imagery. Get a Coffee Please !. Where to get Imagery ?. Most of our imagery are located in the R: SLKBMG ‘Imgwhse’ We also have an IMS server to store some provincial imagery with less detail (mosaic mostly)

suchi
Download Presentation

Tier 2 Training

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Tier 2 Training Imagery

  2. Get a Coffee Please !

  3. Where to get Imagery ? • Most of our imagery are located in the R: SLKBMG ‘Imgwhse’ • We also have an IMS server to store some provincial imagery with less detail (mosaic mostly) • iMap cannot open 1 terabyte at once, this is why the imagery in iMap is located in the IMS server, and not as current as R: drive • We will not be talking about the IMS server, only the R: drive • The R: drive has different types of imagery, and is difficult to navigate

  4. What is inside the Image Warehouse • The different types of imagery you will find in the R: drive are • Orthophoto • Satellite Imagery (Spot5, Landsat5) • DEM (Digital Elevation Model) • Scanned Imagery • Normal Camera Imagery

  5. Raster Data • All all our fine imagery and DEM are in raster format • Each imagery is broken down into many cells • The smaller the cell size, the better the resolution • The smallest cell size is what we are concern about • The smallest cell size of 1m x 1m has a better • resolution than 2m x 2m • Colours are shown better with a smaller cell • size 1m 1m 2m 1m 2m

  6. Airphoto • An air photo is created when a small private plane fly through an area with a special camera and take a photo • An air photo can only capture a certain distance depending on how high or low the aircraft fly • The lower the aircraft fly, the better the detail it will capture, but it will also cost more money • The lower the aircraft capture, the higher the resolution, and the lower the ratio of scale it is • 1:20,000 has more detail than 1:50,000

  7. Orthophoto • Every airphoto has distortion because it is taken in an angle in some ways • In order to correct distortions, “Orthophoto” is born • Traditional, an Orthophoto is created when a person sits down and correct for location distortion for certain distance throughout the photo

  8. Mosaics • Each Orthophoto has around a size of 1.5 gig per tile, so we split them up in 20k(1:20000) mapsheet • Also because the aircraft can only take certain distance at a time, we grouped up the airphoto as a continuous photographic representation and we called it a mosaic map. • Because loading 20 Ortho 0.5m at once (20 x 1.5gig= 30 gig) takes a long time, most mosaic photo you find in the R: drive will not retain its detail, so its hard to find a real 1m Ortho mosaic photo of the whole province without losing details • How much is lost in the process I do not know • Mosaic photo applies to satellite imagery as well for continuous photographic map

  9. Satellite Imagery • Nowadays, satellite imagery can match the detail of an Orthophoto • The two most common satellite imagery in our image warehouse is Spot and Landsat Landsat 5

  10. Landsat Imagery • Most of our newer imagery are Landsat5, but there are some earlier years with Landsat7 • From Landsat5 imagery, we have usually 543, and 321 natural colour band of most of the province • We have it covered the whole province every year, our newest ones are 2006 (2007 coming) • The Landsat5 imagery are 30m, which means good price • Because of its lower resolution, it can cover more area, less size, and less loading time

  11. Spot Imagery • We currently have Spot5 imagery that we purchased from TELUS • They(Satellite People) can pinpoint the Satellite to where ever they want to snapshot, so there is no index for the original files • We only acquired B&W spot5 imagery from TELUS • The B&W spot5 imagery are 5m • In order for us to get a spot5 colour imagery, we fused (coloured) the spot5 B&W with the Landsat5 30m with different colour bands, and than BMGS renamed it spot5 5m colour enhance imagery

  12. Questions?

  13. So how do we find these imagery? • We have index files for these imagery • Most of these index files are related to mapsheet • Most common mapsheets are 1:20,000 and 1:50,000 • Different mapsheets of the whole province can be found in LRDW

  14. Map sheet 20k/50k 1:50,000 1:20,000

  15. Orthophoto search • Find the 20k mapsheet number for your area (93K049) • Either ArcCatalog/Explorer, go to R: SLKBMG • Look through the folder Ortho 2006/2005 with the number headings • If your mapsheet number is 93K049, you look under 2005 ortho and search under 93k folder • Find the file name bc_093k049_xc500mm_utm10_2005 and drag the file into ArcMap • If you can find it in Ortho 2006, than try Ortho 2005 folder

  16. Orthophoto search (Continue) Location File name

  17. Searching for Spot5 imagery • There is no index for the Spot5 B&W, and no solution to sort them out (ask BMGS people) • However, the colour Spot5 imagery are broken down into 50k mapsheet • Using the same procedure to find Ortho photo, you use 50k mapsheet over 20k mapsheet • Spot5 B&W path R:\satellite\spot\scene • Spot5 Colour path R:\satellite\spot\maptile

  18. Searching for Spot5 imagery (Continue) Spot5 colour file path Notice the 50k mapsheet numbering

  19. Searching for Landsat5 imagery • Landsat doesnot use mapsheet index • Landsat’s own index is located in • R:\satellite\landsat\scene\landsat_master_wrs_index • Once the file added added into ArcMap, the labeling is a little complicated • Go to properties and go to labels and press expression • Clear the bottom expression, double click “Path” so its added and than one click on “ROW” and press “Append”, than press OK • the final expression should be like this “[PATH] & " " & [ROW] “

  20. Searching for Landsat5 imagery (Continue) • Fort St. James is located near the number “4922” • Landsat imagery located in the following path • R:\satellite\landsat\scene\2006\tif\(bcalb or utm10)

  21. Searching for Landsat5 imagery (Continue2) Landsat Path Filter File name

  22. What to Remember • Only use Orthophoto if you need that resolution, because it takes a lot of load time if you open a few of them • ArcGIS 9.2 has a bug of loading 5-10 times longer than 9.1, so use ArcGIS 9.1 if you want to view imagery in ArcMap • Landsat imagery are usually the most updated one because of its price • Spot5 imagery has its limitation and complexity in colour format • Orthophoto is not covered across the province of the same year • If you have Questions call BMGS people like Angus Christian

  23. Questions?

  24. DEM • DEM (Digital Elevation Model) is for looking at elevation of certain area • Our best DEM’s in the warehouse are 25m for the smallest cell size • The elevation data generates slope, aspect, and hillshade data • We cannot make a 15m hillshade off a 25m elevation data • DEM are searched in 50k mapsheet • DEM data are found in the following path • R:\dem\

  25. DEM • For better break down of the data, on elevation, slope and aspect data, you need to go into properties and under the symbology tab, and press classified instead of stretched to see better differences Change to classified

  26. DEM Display

  27. Questions?

More Related