5.3.1 Import raster map from external source - LUPMISManual

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5. Conversion of data > 5.3 Raster maps

5.3 Raster Maps

5.3.1 Import Raster Map from External Source


Level of expertise required for this Chapter: Intermediate; specifically for LUPMIS @ TCPD

After having received data files from another agency or institution, you have to check for their format, resolution and projection. If these are ok, read following Chapter 5.3.2 for the procedure to quality-check the images.

General process to import raster files to LUPMIS: Format conversion (to JPG) --> Reduction (to 60-100 cm) --> Projection (to UTM 30) --> Mosaicing


or, if in incompatible, multiple-layer TIF file (see note 2 below):
Format conversion (TIF to JPG in Paint Shop Pro) --> Rename TIF to JGW --> Convert format (and save under different file name/folder) -->   Reduction (to 60-100 cm) --> Projection (to UTM 30) --> Mosaicing . Not all steps are always necessary.

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A) Format

Is the image in
JPG or BMP or TIF or ECW format or other?

As TIF (or BMP) files are very large and slow, it is better to convert them to JPG files:
Main menu > Utilities > Bitmap utilities > Convert file format > from …> Select folder and file > Open > Save as window: Serve as type: JPG > Specify file name > Save > Select calibration option window: Map Maker calibration > OK

ECW format produces compact (i.e. relatively small) files, but can not be processed by some GIS installations in Ghana. It is therefore recommended to convert ECW files to JPG format. (See also Annex 10 on standards).

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Note 1: If the TIF file is very large, Map Maker might not clean up the memory after the process. If you observe strange behaviour of the system afterwards, just exit Map Maker and reload. There is no problem with the converted JPG file.

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Note 2: There are a large number of TIF ’subformats’ (not only GeoTiff). If data are provided by in either corrupt or incompatible, non-standard or multiple-layer format, the conversion process as described above suddenly might stop, and the system crashes. You have to fix these data:

Either (much faster, but not always successful) through:
Main menu > Utilities > Bitmap utilities > Convert file format > Convert multiple files > Select folder with source files > Files of type: TIF > Select the TIF file(s) (if many, with the shift key) > Open > Select target directory > OK > JPG > Map Maker calibration > OK


Or through following steps 1-3:

1. Load IrfanView (supplied on  LUPMIS distribution CD). Use the batch conversion option to change multiple TIF files to BMP. (Experience level required: advanced).

You can use also Paint Shop Pro or any other graphics program, which can load TIF files, and load the incompatible TIF file, but don’t resize, don’t clip, don’t change canvas, don’t make any changes. Only, save as BMP file (in Paint Shop Pro:
Main menu > File > Save As… > Save as type: BMP > File name: You can keep the file name, but without extension (BMP will automatically be added) > Save ).

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2. In Windows Explorer, locate the ‘world file’ with the extension TFW and the same file name as the original TIF file. Keep the same filename and in the same folder, but rename the extension TFW to BMW (
right-mouse > Copy, then Rename). If there is a warning message about changing the extension can make it unusable, ignore it by: Yes.
For example: Kasoa_789656.TFW should be renamed to Kasoa_789656.BMW.

Alternatively, if you have a file name converter utility, for example 1-4a Rename (contact TCPD-HQ / LUPMIS or at www.1-4a.com/rename/, freeware), you can also batch-convert all TFW extensions to BMW. Or, you can use IrfanView for renaming (Experience level required: advanced).

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3. To be consistent with all other JPG files in LUPMIS, convert the world file calibration to Map Maker internal calibration:
Main menu > Utilities > Bitmap utilities > Actions > Select folder > Select file type: JPG > Select the file from the previous step > Open > Transform window: Convert format > Convert bitmap from one format to another > OK > Save as window: Select file type: JPG > Enter new file name > Save

Alternatively, you can use the batch conversion of Map Maker:
Main menu > Utilities > Bitmap utilities > Convert file format > Convert multiple files. You batch-convert from BMP (with world files) to JPG (with Map Maker calibration); or directly - if possible - from TIF to JPG (with Map Maker calibration). (Experience level required: advanced).

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4. You might have to rename the file to follow the standard naming syntax: See  Annex 1.2 about LUPMIS technical standards.

Alternatively, you can use a file name converter utility, as mentioned above. (Experience level required: advanced).

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5. It is a good practice to check the product after each of these steps displayed with GPS data (for example, roads) on top.

See Annex 2.3 with information about 'world files'.

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Note 3: If you have many files to be converted, you can use the multiple file option (but you should not attempt to batch-convert ECW files).

1. You better first create a temporary folder. You can call it Temp_source, and copy all files to be converted into it.

2. You better also create another temporary folder and call it Temp_target.

3.
Main menu > Utilities > Bitmap utilities > Convert file format > Convert multiple files > Select folder (e.g. Temp_source) > Select file type > By dragging the cursor, you select all files (They then should be all listed in the file name box, each with ") > Open > Choose target directory window: Select the target directory (e.g. Temp_target) > Ok > Choose target file type and calibration method window: For LUPMIS, select JPG and Map Maker calibration > OK

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B) Resolution

Check the file size and display the image in Map Maker (
Right-mouse > Project Manager > Add Layer). Zoom in to an extreme level and measure the width of 10 pixels with the Tape-tool from the toolbar at the left.



A good compromise between sufficient level of detail for land use planning and easy file handling is a pixel size of 80 cm (- 100 cm).

The sample above shows a pixel width of 20 cm (2 m for 10 pixels), which is by far too detailed (‘overkill’). Calculate the reduction factor, for example:

  • If the pixel size is 0.20 cm: Factor of 4 produces pixels of 80 cm width: Reduction factor of 1/4 = 0.25

  • If the pixel size is 0.60 cm: Factor of 1.333 produces pixels of 80 cm width: Reduction factor of 1/1.333 = 0.75

  • If the pixel size is 80-100 cm: Do not reduce, no need for action


Process through Main menu > Utilities > Bitmap utilities > Reduce size > Reduce size of one file > Select file type JPG (from previous step) > Select folder and file name > Open > Transform file window: Write to a new file > Save as type: JPG > Specify new file name > Save > OK > Enter multiplication factor window: Enter reduction factor from calculation above > OK

See part C of  Chapter 5.3.2 and Chapter 5.3.3 for similar descriptions, part F of Annex 2.4 for description and samples of resolution.

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If you reduce the pixel size, it is recommended to keep also the original set. You might need it for detailed mapping (see Chapter 7.3).


Following resolutions are recommended, and necessary for operation of the 'Printing Tools' (see also table of part D below for mosaicing):

  • For detailed mapping: 40 - 60 cm or even better ('high resolution')

  • For Local Plans: 80 (-100) cm ('medium resolution')

  • For Structure Plans and land use mapping: 160 (-200) cm ('low resolution')

  • For Framework Plans (SDF) and overviews: 320 (400) cm ('very low resolution')


Follow the file name syntax, see part F of Annex 1.2 and Annex 10. For automatic Printing Tools see also Chapter 8.3.

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Check for level of details: Can you recognize sufficient details (houses, roads etc).

Get a general impression: Check also for the colours and contrast: Does it look good?

Note: If you have many files to be resized, there is also a multiple-file option, similar to the batch conversion of files, as explained in note 3 (under part A: Format) above (Main menu > Utilities > Bitmap utilities > Reduce size > Convert multiple files).

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C) Projection

Are the data un-projected (lat/long) or in UTM projection or War Office or other?

Load the image into Map Maker and read the coordinates at the bottom left corner:

  • If there are two figures in meters and two in degrees, with an N value (Northing) of between 7 and 10 degrees, it is most likely projected in UTM 30: Ok. (See also  Annex 9 for possible meter figures).


  • If there are only two figures (W or E, and N), with N between 7 and 10, it is most likely un-projected, i.e. in latitude / longitude (see below): The map has to be georeferenced (see  Chapter 5.3.3).


  • If there are two figures in meters and two in degrees, but the Northing value is less than 5 (like 0.9075 in the sample below), the projection is most likely in War Office (Ghana Grid), either in meters or in feet: This map has to be georeferenced to UTM (see  Chapter 5.3.3).


See Annex 2.1 to identify the projection system and similar check for projection of vector maps in part B of  Chapter 5.2.1.

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D) Mosaic  

If the tiles are too small, i.e. too many files are covering the planning area, you have to bring them together to a mosaic with the mosaic-tool. This is often the case with aerial photographs.

Main menu > Utilities > Bitmap utilities > Mosaic and clip > Mosaic and clip calibrated bitmaps window: Add file (1, see below) > Select file type: JPG > Select folder and file > Open > and repeat for all files, you want to bring together > Check that Map Maker calibration is ticked (2) > OK (3) > Select file type: Recommended at LUPMIS is JPG > Specify new file name, preferably according to the map index > Save



Construct an index system, where the name of the tile corresponds to the bottom left corner of the tile (in km, see part B of  Chapter 5.3.2  for illustration, and  Chapter 3.7 for the procedure to create a grid). Do not create too large files. Try not to exceed 4000-6000 KB per file.

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A tile system of 2 x 1 km will have too many files in a planning area. It is recommended to aggregate them with this mosaicing operation to a tile system of 6 x 3 km (6 km in W-E direction, 3 km in N-S direction). At a resolution of 80 cm (like QuickBird’s) this will create files of some 5000 KB.

The higher resolution image files (of 40-50 cm, as explained in Chapter B above) should not be mosaiced together. This would create too large files.

Following tile sizes resolutions are recommended (see also part B for resolution):


Use

Resolution

Tile size

Example file

Code

Detailed mapping

40 - 60 cm

2 x 1 km

7890345_2008_2x1_40

PH

Local Plan

80-100 cm

6 x 3 km

7890345_2008_6x3_80

PM

Structure Plan,
Land use mapping,
(Standard for planning)

160-200 cm

12 x 6 km

7890345_2008_12x6_160

PL

Framework,
Overview

320-400 cm

24 x 12 km

7890345_2008_24x12_320

PV


Note: Resolutions higher than 40 cm will not be considered for automatic printing through the Printing Tools.

Follow the file name syntax, see part F of Annex 1.2 and Annex 10. For examples of index maps, see references to flight index mosaics through Annex 9.

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Images can also be too large (often, satellite images). It is then recommended to break it down into individual tile for easier and faster handling. This is explained in  Chapter 5.3.8.

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See also part B of Chapter 5.3.2 for quality-check of raster images: Rectangular shape.


  



 
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