© 2019 SPH Engineering www.ugcs.com

version 3.2 (113)

UGCS mapper

User Manual

Table of Contents

Installation and System Requirements 3...................................................................Useful links 3.............................................................................................................Overview 3.................................................................................................................Operating UgCS Mapper 3........................................................................................Advanced options and settings 8..............................................................................

Cameras 8........................................................................................................................Output 8............................................................................................................................Processing 8.....................................................................................................................Advanced 9.......................................................................................................................Geoservers 9.....................................................................................................................Output data format 9........................................................................................................

Considerations 9.......................................................................................................Troubleshooting 11....................................................................................................

Logs 11.............................................................................................................................

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Installation and System Requirements • Windows (7,8,10)

• macOS: El Capitan 10.11, Sierra 10.12

• Linux Ubuntu 16.04.

Useful links • Diverse basic instructions for setup and import

https://www.ugcs.com/en/page/ugcs-how-to-instructions

• Detailed information on UgCS various application scenarioshttps://www.ugcs.com/en/page/photogrammetry-tool-for-land-surveying

• Frequently asked question page with most common questionhttps://www.ugcs.com/en/page/faq

• Visit UgCS YouTube channel with various tutorials, webinars and videoshttps://www.youtube.com/user/ugcstv

Overview UgCS Mapper is a desktop software designed to create offline 2D maps in minutes. In-field assembled map provides certainty for UAV surveyors that acquired images quality and density is sufficient. This information is crucial to decide whether the flight should be repeated before leaving surveying area.

Another feasible value of UgCS Mapper is for drone missions, that has to be flown in places with insufficient quality of publicly available map. Shortly after the first flight a more detailed map of the surrounding can be created for more precise planning.

Operating UgCS Mapper 1. Download UgCS installation from https://www.ugcs.com/download. Please, note that UgCS

Mapper is installed as separate component, do not forget to check mark it when installing.

2. Install UgCS on a clean machine and run UgCS service manager.

� Figure 1. Shortcut on Windows desktop to run UgCS service manager

3. Check that the Geoserver is running.

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� Figure 2. How to check that Geoserver is running

4. After installation, the UgCS Mapper icon will be located on the desktop (Windows).

� Figure 3. Shortcut on Windows desktop to run UgCS Mapper

5. Run UgCS Mapper:

� Figure 4. Window displayed when UgCS mapper is launched

6. Note that images for processing should be georeferenced, e.g. EXIF data should contain GPS coordinates of the camera.

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7. Select directory with images, select or create output directory and click "Process".

8. Note that if the camera is not calibrated, the following window will be displayed:

� Figure 5. Camera calibration

For best calibration result, select the folder with the set of images taken nadir from same altitude on the same AGL (Above Ground Level.

When calibration is complete, the following window will be displayed:

� Figure 6. Camera calibration complete

Click the “output directory” link and open “Report” file. If the calibration results is satisfying – click “continue processing”. The UgCS Mapper will process the rest of the images. Finish button will stop the process to reset and recalibrate the camera.

9. After processing is complete, you'll find orthophoto.tiff with stitched map and report.html with processing report. Right-click “The output directory” in the last window to see the output files. In the root of the output directory application generates the following files:

• Geotiff

• MBTiles

• Processing report HTML

• Logs.

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10.“Preview map” allows to preview the project, with Layers taken from geoserver

� Figure 7. Map preview

11.“Publish” button allow to publish data to selected geoserver.

� Figure 8. Publishing parameters

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Map and elevations will be imported to UgCS with the name that was used when published the project.

� Figure 9. UgCS map layer tab

� Figure 10. Screenshot of UgCS map view

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� Figure 11. Screenshot of terrain view in UgCS

Advanced options and settings Click the “gear” button to open settings menu.

� Figure 12. UgCS Mapper setting button

Cameras Cameras – The location of you calibrated cameras, which can be recalibrated by right-clicking and clicking “Set uncalibrated” button

Output File types that will be used as output formats for the complete project.

MBTiles - MBTiles is a file format for storing map tiles in a single file. It is, technically, a SQLite database.

Map/Terrain GeoTIFF - Georeferenced Tagged Image File Format (GeoTIFF) is an open file format and de facto standard based on the TIFF format and is used as an interchange format for georeferenced raster imagery.

Processing Processing - Exposure correction method 

Algorithm used to compensate exposure difference on different shots. Note that good shots should not have much difference of exposure. Having it means that photogrammetry shooting recommendations most probably were not followed (e.g. exposure was not set manually, weather was too shiny with varying lighting conditions).

Histogram equalization - this method tries to equalize luminance channel histogram for each picture. It is able to smooth local dynamic exposure variations on a separate pictures (like cloud shadows). Side effect is slight color distortion, which makes the result to look less natural. However, this method is the most universal and thus is default.

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Color correction - analyzes exposure difference graph for all pictures at once and selects correction factor for each picture. The difference is estimated for a whole picture, correction factor is also applied to a whole picture. It means that local dynamic exposure variations cannot be effectively smoothed. This method usually produces bad result for pictures with too significant exposure variation. For good pictures it may produce the best result, preserving natural colors and shading.

None - do not attempt to fix exposure difference. Use it if it is required to see original pictures, or other methods produce unacceptable results.

Advanced Image size for features extraction - images are downscaled to this size before features detection and extraction. Downscaling discards small details, leaving larger ones for detection. Reducing this parameter value may help to improve result for photos with overwhelming high-frequency noise (e.g. trees, bushes, high grass; wind usually makes it even more noisy).

Geoservers This tab is used to indicate the server address, the data will be sent to. By default, it is set to local computer. To change it, click “Add” button and enter the desired address.

Note, that it’s not possible to have several servers added to the list. To edit server address, select it by right-clicking and click “Edit”.

Output data format TIFF file stores image data in chunks. There are two major types of chunks: strips and tiles. Each chunk is compressed separately (in case if compression is used). Each strip is a group of consequential scanlines . Tiles are rectangular regions of equal sizes (except rightmost and bottom-most tiles), size of equals defined in file creation.

We use tiles, because of the following benefits:

• Scalability. In process of building TIFF file, we need to provide full scanline at once if we are using strips. It means that we need to keep in RAM all tiles of that row, which might consume a lot of RAM for big/detailed map. And there is always may exist such map which will need more RAM than installed. With tiles, we consume more or less, constant amount of RAM independently of map size. 

• Performance. Mapper internal storage is implemented in tiles, which are one-to-one mapped to TIFF tiles. That saves a lot of processing.

• Space. Usually map has irregular shape. However, the TIFF image data is represented as rectangular region. It is possible to skip tiles in TIFF, which is used in mapper, so empty tiles are not created in the file.

Notice that output TIFF file could be open only in GIS.

Considerations • We don't recommend fly backwards. Collect all of the data while drone is moving forward.

Most aerial cameras have rolling shutters, that is why mixed forward and backward flight ruins the chances of turning out the task well.

• Collect images at a consistent speed. All images for a set should be collected on the same speed as it possible. With a rolling shutter, images taken at differing speeds will have different geometries and harm the accuracy of the final files.

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• Preprocessing. Images should not be processed to remove lens distortion. Color correction is possible, but make sure the tags are intact.

• Overlap. Along pass and across pass overlap should exceed 70%. More complex scenes requires more overlap.

• Exposure time vs speed. Try to keep the ground smear below the GSD value. 15 m/s flight at 1/1000s exposure will allow 1.5 cm GSD.

• Contiguous. All images must share a common boundary. Don't upload non connecting sections or separate of coverage islands.

• Job shape. When doing long, linear works, please, make sure to have at least two passes so there are enough perspectives to reconstruct the scene. Increased overlap will need to be used to make up for the lost width.

• EXIF tag accuracy. Camera GPS Workflow images should have geotag accuracy of less than 10 m and contain elevation values. Also, precision should be reported with at least 3 decimals of seconds precision. In this format - DD:MM:SS.SSS, not in this - DD:MM:SS.000.

• EXIF tags are intact. EXIF tags should not be modified by 3rd party image processing software. We need all of the camera tags originally placed in the image files. Photoshop, Photos, Photo Manager and many other applications are known as ones to corrupted the tags.

• Inclusion area. Be sure to fly over areas that needs to be included in the map. We сut the jagged edges off and the best way to make sure something will be included is to fly over it or make sure it is within the interior of the flight path.

• Repeating patterns. Since our processing is based on matching similar features, target areas with repeating patterns, such as roofs or crops, can confuse the application and became the reason of low-quality outputs.

• Terrain. Terrain greatly affects to overlap. If the terrain rises from the nominal overlap planning point it will be reduced. If the terrain drops from the planning point, it will be increased. Take the high point of the survey area into account.

• Weather conditions. Clouds will affect the amount of light that is available and winds will affect the symmetry of the ground speed from pass to pass.

• Cruising altitude images only. Only images that taken at the cruising altitude should be uploaded into the system. Please, do not upload images from different altitudes, like than what taken during ascent and descent.

• Minimize the Inclusion of water because it moves constantly or it is indiscrete.

• Avoid sun glare and highly reflective surfaces (like roofs of large buildings and wet pavement).

• Use high overlap in trees areas because they are typically in motion and have a lot of fine details.

• Cameras with a super wide field of view or fisheye lens are not suitable for mapping applications.

• Avoid overexposed and underexposed Images. We recommend the ahead surveillance of the area, taking some exposure test images to determine the values that will work.

• If objects in the scene are moving, the processing gets confused and can generate positional errors.

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• Do not attempt to stitch vertical surfaces.

• Any images that include the horizon, should be kept out of the upload list.

• Only Nadir (straight down) images should be used.

• Avoid mapping late in the day when the sun is low and the shadows are long.

Troubleshooting

Logs To provide support for certain questions and issues UgCS logs would be required. Logs are store in the following locations:

• For all systems – Selected output directory.

Messages Resolution

Start geoserver and click retry (step 2, running UgCS service manager).

Skip terrain generation – map will be generated without terrain 3D model.

Use average elevation value for the area – enter the average elevation height above sea level for the scanned area.

Error 503: The geoserver cannot fetch data from upstream server

Most likely the problem is within internet proxy server or firewall. Check proxy and firewall settings.

Elevation binding failed

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