erdas 2011 manual

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ERDAS Imagine Customer Education

ERDAS Customer Education

ERDAS Imagine

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Table of Contents

1. Geo-Referencing of Toposheet 3-14

2. Importing of NRSC Satellite data 15-17

3. Geo-Referencing of Panchromatic data 18-25

4. Image Subsetting 26-27

5. Resolution Merge 28-31

6. Stitching of Images 32-41

7. DEM Generation 46-53

8. Change Detection 54-56

9. Classification 57-61

10. Vectorization 62-76

11. Map Composition & Symbol Creation 77-95

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Erdas Imagine Ribbon Window Termology

Mouse Conventions

LMB Left Mouse Button

RMB Right Mouse Button

MMB Middle Mouse Button

Quick Launch Ribbon Menu

Ribbon Tool Bar

2D View

Contents

ShoeBox

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Geo-Referencing of Topo-sheets

1. To Geo-Reference scanned raster SOI surveyed toposheet data. Open Raster toposheet data into viewer by using RMB click on the screen.

2. New dialog box appears to Select Layer to Add then select 57f2.tiff

file, click OK to open.

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3. On erdas imagine software ribbon click on Multispectral menu, click on Transform & Orthocorrect submenu control points to provide Geometric model.

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4. Select Polynomial as on Set Geometric Model on Model list and click OK.

5. GCP Tool Reference Setup dialog box appears to collect Geographical

reference point source, select the option Keyboard Only for toposheet

map then click OK.

6. Click on Reference Map Information click on Set to get the Projection

chooser dialog box.

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7. On Projection Chooser window click on the

Custom Tab and set projection parameter as –

Projection Type Geographic Lat/Lon

Spheroid Name Everest 1956

Datum Name Indian (India, Nepal)

then click OK

8. Polynomial Model Properties dialog box appears, click Close to proceed.

Note: There are 16 reference points in a Topo sheet the lat/lon values of

all these points are shown on the Topo sheet.

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9. Click Create GCP icon on Multipoint Geometric Correction tool bar

.Move the mouse cursor on the viewer, cursor will turn as ‘+’ like

cross sign on the viewer then take cursor to the top left corner of the

grid on the toposheet and click LMB button. GCP point gets placed at

corner of toposheet map grid then GCP point input values comes as in

GCP Tool (X input and Y input).

10. For same GCP point input value for X Ref 77 and Y Ref 14 45(to input

values use space bar eg. to enter 14 45’, type 14 press space bar then

type 45).

11. Follow the same above step to create second and third point on toposheet on other grid corner.

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12. As after third point onwards point reference values need to provide as input for column Xref. and Yref. then software starts point prediction automatically on the toposheet, if it is required adjust the same GCP

point to the exact location. 13. Follow the same step for remaining another 12 GCP points on the

toposheet grid.

14. As after placing GCP points, save the points by clicking file/save input

and save reference in multipoint geometric correction window.

15. Create a folder name ERDASOUT on your local drive where output data a

be saved. Click on Multipoint Geometric correction tool display resampling image dialog, Resample dialog box provide TOPO-GEO as output name on ERDASOUT directory to take resample output and make sure to ignore zero stats.

16. As after removing toposheet non-georefrenced image from contents by

clicking LMB remove layer then open the resampled output topo-geo

image in same viewer.

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17. On erdas imagine software ribbon click on Multispectral menu, click on

Transform & Orthocorrect submenu Reproject to reproject the

georefrenced geographic toposheet into polyconic projection.

18. Reproject Images dialog box appears to change projection system as Polyconic

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19. On Projection Chooser window click on custom tab to provide input under as parameter-

Projection Type Polyconic

Spheriod Name Everest 1956

Datum Name Indian (India, Nepal)

Longitude of central meridian

77 07 30

Latitude of origin of projection

14 37 30

then click on Save button and save projection as polyconic-india in category polyconic click OK. Save the custom projection as in Polyconic new category and use the same projection from standard projection tab to select polyconic-india then click ok.

a. On Reproject Images dialog box provide output name TOPO_POLY, ignore zero stats and click OK.

b. When the process is over. Click Close on the progress bar.

20. Same viewer removes other layers from contents box by RMB click

remove layer.

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21. Open the resampled output file (topo-poly.img) in a viewer to verify

the output file. On viewer menu click on utility/inquiry cursor, place

the cross hair to the know location (where longitude and latitude values

are printed on Toposheet). Select top left corner list box option from

map to lat./long., so for known values on toposheet grid this software

interface values has to be very close to each other values.

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Importing of NRSC Satellite Data

The ERDAS IMAGINE Import function allows importing a wide variety of data

types to use with ERDAS IMAGINE and other Software. The Export function lets

convert image (ERDAS IMAGINE .img file format) files into other several data

formats.

1. To Import IRS 1C/1D Satellite Data (Super Structured Format). On

erdas imagine software ribbon click on Manage menu, click on tool bar

Import Data to get import dialog box.

2. Choose the format by using drop down list, select IRS-1C/1D(Super

Structured format) and browse Input File

pan/product1/imagery.pan. in the Output file enter pan.img and

click OK.

3. New Information Import IRS-Data in Super Structured Format

dialog box, which provides all the details about satellite data.

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4. Click Import Options button to get Import Options dialog box, click

to check on Ignore Zero in Output Stats then click OK on dialog

box.

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5. Click OK to get the progress bar, after completion of 100 Percent on

Progress bar click DONE and open the imported pan image in the viewer

after removing all the layers.

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Geo-Referencing Panchromatic Data

To Georefrence imported pan Image with the reference of topo-poly georefrenced data.

1. On erdas imagine software ribbon click on Panchromatic menu, click on Transform & Orthocorrect toolbar control points to provide Geometric model.

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2. Select Polynomial as on Set Geometric Model on Model list and click OK.

3. On GCP Tool Reference Setup, select Image layer (new viewer) and click ok.

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4. 5. Dialog box appears to choose the reference image layer. Select topo-

poly.img and click OK. (This will be acting as reference image). Reference map information dialog box appears and click OK.

6. As after providing three GCPs point, automatically prediction of point

gets starts. So place a point in one image, same GCP point will get

placed in another image automatically. If it is required adjust the same

point to identified correct location.

7. Collect sufficient number of GCP points and save it. Click GCP Tool menu

file/save input and file/save reference for the GCP points.

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8. Total RMS error can be checked by point respective GCP Tool Column.

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9. Click on Multipoint Geometric correction tool display resampling

image dialog, Resample dialog box provide Pan-poly as output name

on ERDASOUT directory to take resample output and make sure to

ignore zero stats.

a. To check the correctness of output image with referenced

toposheet, on Erdas Imagine ribbon quick launch panel and open

output image pan_poly.img.

b. To overlay corrected topsheet, in same viewer select quick launch

panel open topo-poly click on raster options tab to disable

clear display and click OK.

c. Rectified toposheet will get overlaid on rectified image. by using

RMB click on the same viewer select Swipe option .

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d. Viewer swipe dialog box appears use mouse to move Viewer

Swipe nudger between 0 – 100,as the toposheet will move on

rectified image. so features of toposheet has to match with

features of image.

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Image Subsetting

To clip image layer using Area of Interest (AOI).

1. Remove all by using layer by using ribbon quick launch then Open

pan_Poly.img in a viewer then click on Drawing menu and select Insert Geometry Rectangle button from displayed toolbar to create rectangle

AOI. So able to create Area of Interest by digitizing the rectangle on the image.

2. To subset image click on ribbon menu RASTER toolbar subset & chip sub menu Create subset Image to open subset dialog box.

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3. In Subset dialog box make sure input as pan_poly.img and output box

type pan_sub.img. Check to Ignore Zero in Output Stats and Select

AOI Button in the subset dialog box to provide subset coordinate

information.

4. In choose AOI dialog box, select viewer radio button. Click OK in

choose AOI dialog box then OK in Subset dialog box.

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5. When process get over click on close button on process list and check the subset layer by opening image in viewer by using quick launch open.

6. Save the AOI layer by RMB click on content aoi layer Save layer as,

specify the layer name as study.aoi and click OK for future use.

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Resolution Merge To Generate Pan Sharp Image by using MSS and Pan Geo-corrected image.

1. As after removing all layer from ribbon quick launch Clear View open Liss-output image in the viewer to subset up to same data extent by using study.aoi layer.

2. Click on ribbon Raster menu Geometry subset & chip toolbar create

subset image sub tool to open Subset dialog box.

3. Make sure input image is Liss-output and browse local directory to type

output name Liss-sub, Check to Ignore Zero in Output Stats.

4. Select AOI Button in the subset dialog box, At new choose AOI dialog box, select AOI radio button to browse study.aoi file and Click OK in choose AOI dialog box then OK in Subset dialog box.

5. The Progress Bar appears, after 100% job status appears click Close

button.

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Resolution Merge

1. Click on ribbon menu Raster menu resolution pan sharpen tool Resolution Merge to get resolution merge dialog box, browse to provide input sharp image as Pan-sub and MSS image as Liss-sub and browse to provide output name in local same directory Pansharp.

6. Select method as Principal Component radio button under Method,

Cubic Convolution radio button under Resampling Techniques, Ignore zero in Stats check box under Output Options and type 3,2,1 in Select Layers the click OK to proceed.

7. Progress Bar comes up, which shows the status of the job, click OK after completion.

8. Open three 2d Views from Home menu window toolbar Addviews subtool bar create new 2d views.

9. Open Pansharp image in first 2d viewer, in second pan_sub.img, and

liss_sub image in third individual viewer.

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10. Set the scale to 12500 by selecting Home menu Extent toolbar in each

viewer.

11. To Geolink all three viewers, on Home menu window tool bar Link All Views select Link All Views to link all viewers.

12. By visualizing all images, output Pansharp image have sharp color

multi spectral resolution.

Note: Pansharp image have both spectral information and spatial information in merged data.

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Stitching of Images

Seamless Mosaicking of three Different images.

In this exercise, different time period satellite LANDSAT MSS and TM overlapping images get seamless Mosaic with each others. The three input files to be mosaicked as: wasia1_mss.img, wasia2_mss.img, and wasia3_tm.img. 1. Click on Raster menu Geometry tool bar Mosaic subtool Mosaic pro

then new window comes up as Mosaicpro. 2. In the MosaicPro Toolbar, click on the Add Images icon, then Add

Images for Mosaic dialog gets opens.

3. In the Add Images for Mosaicking under File tab, select Wasia1_mss.img,

then select “Image Area Options” tab and click Compute Active Area radio

button to enable it then click OK. The file wasia1_mss.img displays as image number 1 in the canvas of the Mosaic Tool viewer.

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4. Repeat steps (2. and 3. adding wasia2_mss.img and wasia3_tm.img to the

canvas of the Mosaic Tool viewer.

5. When the entire three images get added, the MosaicPro should look like the

following:

6. On image list click on column visible to make images visible to visualize their extent.

7. To Cutline Generation Options dialog box and select Geometry-based Cutline

Generation option then click OK to proceed. Images shown with new extent

after generation cutline.

Image List

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Click the ‘display color correction options dialog’ icon in the Mosaic Tool viewer.

8. ‘Color Correction’ dialog gets appears.

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9. Select ‘Use Histogram matching’ check box then Click OK in the ‘Color Correction’ to use function.

10. Click on ’Set Overlap Function’ icon

11. The Set Overlap Function dialog opens to smoothing and Feathering function distance 10 to apply function at this distance.

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12. In the Mosaic Tool Viewer, Select Process/Run Mosaic Output File

Name dialog opens.

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13. In the Run Mosaic dialog under File tab, input name as wasia_mosaic

in the local directory then press Enter key button. Click the Output Options tab, enable the Stats Ignore Value: 0 checkbox, then click OK.

14. The job status dialog displays, showing the progress of the function, click close when the job status dialog reads that the function is 100% complete.

15. Open the stitched image in viewer to visualize it.

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DEM Generation

Digital Elevation Model generation from Arc Info line contour file.

1. Open arcinfo line contour file in 2d view to visualize layer and know

height value in non spatial attribute data column.

2. To know attribute data click on Tool ribbon menu view toolbar Show Attributes.

3. Attribute editor (docable) will get opened, scroll column wise to find the Z value Height (meter) column. Select any vector polyline, so it also gets highlighted in attribute row.

4. Click on Terrain ribbon menu terrain preparation toolbar surfacing tool to open 3D surfacing dialog box.

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5. Select File/Read or Read New Data icon Input Data dialog box

appears.

6. Use Point Data radio button, Under Source File Type select Line Coverage. Under Source File Name select 54L16cont and Under Attribute for Z select IGDS-ZVALUE as height value column, then click OK.

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7. Click OK on progress bar, Values for X, Y and Z are populated in 3D Surfacing dialog box.

8. Click Surface/Surfacing… or Click on Perform Surfacing

icon.

9. Surfacing dialog box will appear give Output file(*.img) name

dem.img use Surfacing Method is set to Linear Rubber Sheeting method.

10. Input Cell Size X as 10 and Cell Size Y as 10, BackGround are set to zero by default and enable Ignore Zero in Output Stats and Output Data Type is set to Float Single.

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11. Click on OK button, progress bar will show the status of DEM generation, after completion of process click OK.

12. To view the DEM, on same 2d View and Open Raster layer dem.img.

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Visualizing DEM in 3D

13. Click on Terrain ribbon menu terrain preparation toolbar Analysis image drape to open Image Drape window.

14. Image Drape window opens to provide DEM.img as input, which

displays DEM in 3D and click Go to Original Position icon in Image Drape window.

15. DEM is fitted in Image Drape window, a link formed in Normal

viewer. Use cursor to change the eye and Target round cross hair, which also updates in Image Drape window.

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16. Close all windows.

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Change Detection Identify and measure the changes between time series data sets.

1. Click on RasterRasterRasterRaster ribbon menu change detection zonal change image difference drape toolbar to open change detection dialog box.

2. Open two 2d view by clicking on ribbon Home menu window toolbar

Add views create new 2d view. In one view open atl_spotp_87.img and in another view open atl_spotp_92.img.

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3. Input atl_spotp_87.img as Before Image and atl_spotp_92.img

as After Image.

4. Input spot_diff.img as the Image Difference File and spot_high.img as the Highlight Change File.

5. In the Highlight Changes, see that As Percent radio button

selected.

6. Change the Increases more than percent value to 20, and change

Decrease more than to 20. Click OK progress bar appears click OK to complete the process.

7. Add more 2d views, in all four Viewers, display atl_spotp_87.img, atl_spotp_92.img, difference.img and highlight.img respectively.

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8. In the viewer which has highlight.img shows only red and green

color to highlight the changes, and then close all the Views.

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Classification

To classify image and determine land cover.

1. Display liss_sub.img image in a 2d view, click on Raster ribbon menu

classification toolbar unsupervised classification.

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2. Select liss_sub.img under Input Raster File. Give output layer name liss_class.img under Output File.

3. Type 8 in Number of Classes, Input 12 in Maximum Iterations and 0.950 in Convergence Threshold, then click OK. Progress Bar comes up. Once it gets completed then clicks close.

4. Display liss_class.img in a new View, by adding 2d view from

home ribbon menu window add views tool bar.

5. Select Raster/Attributes in the viewer menu bar.

6. Raster Attributes Editor which shows specified number of class and other attribute.

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Classes created as:

Unclassified Class1 Class2

Class3 Class4 Class5

Class6 Class7 Class8

Colors as: Gray levels

7. LMB in box under Color column and select the blue color.

8. LMB in box under Class Names and type Water.

9. Proceed for other classes to provide class name. 10. To add AREA column, click on Table ribbon menu column Add Area and

Add Area Column dialog box opens.

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11. Select Hectares in Units and type Area in Name field then click OK. Area Column gets added in Attribute Editor.

Thematic Classified image

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Vectorization

Creating of GIS vector layers, editing and query making on it.

1. Open Erdas Imagine view and Open Raster Layer topo_poly.img

to create new vector layer click on application menu new 2d view vector layer.

2. Create a new vector layer dialog box get appears.

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3. Select Shape file(*.shp) in File of type, Type Roads in File name

and Click OK. New Shape file Type Option dialog box get opens.

4. Select Arc Shape under Select Shapefile Layer Option then click

OK. 5. Vector roads.shp layer is created on image and to use vector tool

for Vectorization click on ribbon drawing menu toolbar insert geometry polyline.

Adding Attributes to Existing Table

1. Click on ribbon Table menu toolbar query column properties. New column attributes dialog box appears new button is used to create new

column.

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2. Type the value in same column and save layer then remove layer.

Editing the Existing Vector Layer

1. Open a 2d View, Open pan_poly.img then open road shape vector layer on it.

2. To make layer editable, click on drawing menu modify toolbar Enable Editing.

3. By using Drawing Menu insert geometry tool creation and editing of

features can be done.

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Creating Attribute based Symbology

Every feature is identified in the vector layer by the attributes assigned to it.

Ex: in the roads.shp file, some roads are given road_id as 10, some roads are given 20 and other roads are given as 30. By default every feature has been given default color and thickness, to use different color and symbology of road by using their attribute column road_id value.

1. Open a new 2d view, Open road.shp Vector layer.

2. Click on drawing ribbon menu Symbology vector symbology toolbar. Symbology dialog box get open.

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3. Select Automatic/Unique Value in the Symbology dialog box.

4. In the pop up list select ROAD_ID (by using road attribute column new styles are get generated).

5. Enable ‘Generate New Styles’ check box and click OK.

6. In the Symbology dialog box, different color for different id put as

row wise in shape file.

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7. Also able to change color, thickness and line style for each line, use LMB in the cell under Symbol column for Class Name 10 and select Other.

8. Line Style Chooser dialog box get appears.

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9. To change the width of the line, color by using Width text box change value to 2 and by Outer Color selector box choose red color for display then click ok.

10. Follow the steps from 7 to 9 change the color to red and thickness

as 1 for Class Name 20.

11. Class Name 30 is railway line, change the style like rail track.

12. LMB in the cell under Symbol column for Class Name 30.

13. Select Other to get Line Style Chooser dialog box and select Custom tab.

14. In Outer Width type 1 and select color as black.

15. Click on Use Symbol check box, use Other/Symbol Chooser to change symbol.

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16. Select Misc, in the pop up list. Choose Vertical line.

17. Enable on Use Color check box. Choose color as Black.

18. Click OK.

19. Click OK on Line Style Chooser dialog box. 20. We observe different line styles in Symbology dialog box.

21. Polyline in the shape file has been changed to different line styles and colors based on attributes.

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22. Click Close in the Symbology dialog box then attention message

box appears click Yes to save line style, color.

23. Appears Save Symbology As dialog box.

24. Go to the directory where shape file exists and type roads and press

enter key (*.evs files should have the same name as the coverage name, and it has to stored in the same directory where coverage exists).

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25. Click OK and close all windows.

26. Save symbology .evs file ensures to open shape file road with the same style and symbology.

Vector Querying

To make vector query on attribute table click Table menu row toolbar criteria, then

selection criteria dialog box appears.

1. To select a particular feature by writing a query (ex: all roads which has road_id = 10).

2. RMB on any cell under Record column and select Criteria. The Selection Criteria window dialog box appears.

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3. LMB in text box under Criteria LMB on road_id Columns list, select ‘==’ from Compares list and type 10

4. The expressions as $"road_id" == 10, click on Select button and click Close.

5. All records with road_id = 10, which are available as in column attribute get highlighted in the attribute editor and the corresponding features are also get selected in the viewer.

erdas 2011 manual

Documents

gcp points

gcp point input values

reference points

toposheet grid

gcp tool x input

reference values

georeferencing of toposheet

gcp icon