How is the filter parameter applied to a layer?

iGIS stores all its vector data in a SQLite database on the iOS device. A layers defined filter text is applied at the SQLite database level as the WHERE clause component of a SQL SELECT query.

i.e. a defined filter parameter of:

Unit_type IN (‘GP’,’SP’) AND source = ‘GCCT’

would be applied to the target layer as;

SELECT * FROM <target layer> WHERE Unit_type IN (‘GP’,’SP’) AND source = ‘GCCT’;

Filter text clauses just need to be SQLite SQL compliant. http://www.sqlite.org/

Capturing photos and linking them to features

From version 6.0 photos can be captured and linked to features. This is a ‘Pro feature’ provided as BETA functionality in version 6.0, please note that future versions will require Pro features to be activated via an in-app purchase.

To link photos to features you will first need to define an ‘ID field’ for the target layer. To do this Open the target Projects settings, and navigate to the target layers settings.

‘ID field’ attributes are used in the naming of the photos to enable easy linking or GIS software hyperlink creation after export from iGIS.

Photos can be captured and linked to existing or newly created features:

- To add photos to an existing feature, single tap the feature in the map window to display its attributes. Select Edit, Scroll down to the end of the attribute list and select Photos.

- To add photos at the time of feature creation, In edit mode, after the features geometry has been defined, select commit to bring up the attribute window, Scroll down to the end of the attribute list and select Photos.

On USB export from iGIS linked images are exported to a directory beside your exported shapefile data.

The naming conventions for images captured in iGIS are;

<shapefile name>-<iGIS ID Field value>-<Image number for feature>.jpg

i.e.

aus10bgd_r-12-1.jpg

The process of setting up hyperlinks to these images is different depending on which GIS software you use.

The below linked ESRI article describes how to setup dynamic and field based hyperlinks in ArcGIS.

http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?id=241&pid=237&topicname=Adding_hyperlinks_to_features

File size limitation for iGIS USB import

During the iGIS USB import process the zipped data is sent to the apple device and is then extracted. The import may fail on large files if the extraction process runs out of available resources on the device.

We have found the limit to be around a 1.5GB zip file for iGIS v5.1.3 running on the iPhone5 and the iPad with retina display. This limit is not an exact filesize as it is imposed by consumption of available device resuorces, which can be variable.

Empty template shapefiles for creating new point, line and polygon features.

Before you can create and edit features in iGIS you need some layers to store your data in. Layers are created by importing existing shapefiles which have been created in third party software into iGIS. If you do not have any shapefiles, you can download the below attached zip file which contains a template point, line and polygon shapefile. The attached shapefiles should be imported into iGIS using the import settings;

Projection System: [EPSG: 4326] WGS 84 (Lat/Lon)
Characterset: UTF-8

empty template shapefiles – 4326 WGS84

Rendering a layer with feature specific colours

As the shapefile format does not store feature rendering details within it’s shape attribute, iGIS supports feature specific colour rendering via the definition of hexadecimal colour code values within an attribute of the shapefile.

To use this functionality your shapefile will need a ‘Text’ type field containing hexadecimal colour code values.

The below screen print from ArcMap shows a display colour attribute field called ‘disp_col’ containing hexadecimal colour code values per feature.

A shapeifle like the one seen in the image above could then be imported into iGIS, and added to a project with  its  ‘color attribute’ option for the layer set to the ‘disp_col’ attribute.

When the project is opened features for the layer will be rendered with their defined colour.

There are many hexadecimal colour code charts and tools available online.

http://www.colorpicker.com/

Is the iGIS in-App help documentation available in pdf format?

Yes,  please see the below linked pdf document.

http://www.geometryit.com/igis/wp-content/uploads/iGIS-Helpfile-v5.1.1.pdf

Importing shapefile data into iGIS via USB.

Follow the below steps to import your shapefile data into iGIS via USB .

  1. On your computer, add your shapefile data to a compressed zipped folder. i.e. ‘07102011.zip’
  2. Connect your iPhone/iPad to your computer via it’s USB cable, and open iTunes.
  3. Select your iPhone/iPad under DEVICES in the left hand navigation panel [Image 1. (1)] Select Apps [Image 1. (2)] Select iGIS [Image 1. (3)]
  4. Use the ‘Add…’ button to add your zipped shapefile data. [Image 1. (4)] Once the data is loaded it will be listed as per; [Image 1. (5)]
  5. The zipped data will now be on your iPhone/iPad so you can eject your device [Image 1. (6)] and unplug the USB cable.
  6. On your iPhone, open iGIS and select ‘Import’. The import menu open in USB mode so your zipped data will be discovered in the iGIS Documents directory and will begin to extract. All extracted shapefiles will then be listed as per;  [Image 2.]
  7. Select the shapefile and define, it’s projection and character set. Select Import. [Image 3.]
  8. The data will begin loading, and indexes will be created.  [Image 4.]

* If your zip file contains multiple shapefiles of the same projection and character set, you can import all the files together by selecting ‘Import All,’  defining the projection and character set,  and then selecting ‘Import All’ again to initiate the process.

Image 1 - iTunes import steps.
Image 2 - iGIS import steps.
Image 3 - iGIS import steps.
Image 4 - iGIS import steps.

Loading Russian/Cyrillic shapefiles

Several iGIS users are having trouble loading Russian language shapefiles. The trick is to get the right character set. The character set that we’ve had most luck with is ‘Eurpopean Languages – CP1251′ or ‘Windows Cyrillic – CP1251′. Not obvious but it works for at least some datasets.

Loading and using Raster Imagery

In iGIS v5, we have added the ability to load and view your own raster imagery on maps. Many of our users have asked for this functionality, and new features of iOS 4 have allowed us to do it. Working with raster imagery is CPU and memory intensive when done poorly, so we had to think of a process which avoids overloading the iPhone’s resources.

What we have chosen to do is pre-process imagery using an opensource tool, MapTiler. This tool converts many image formats into a series of tiles, similar to the Google map tiles. We then use these tiles in the app as an overlay on the map, allowing us to retain great map speed, since the app doesn’t have to re-project to re-process any imagery. We’re very happy with the results, and hope that you will be too.

Several steps are involved in getting your imagery onto the app, however once you have been through the process a first time, you should find these steps simple to replicate and well worth the effort.

  1. Install the MapTiler software on your PC or Mac – only needed the first time.
  2. Re-project and tile your maps using MapTiler.
  3. Zip up the resulting imagery directory.
  4. Copy the zip file to the iPhone using our importer or via USB (we’ve got USB importing in V5 too).
  5. Add the layer to the map.

To install MapTiler, please download from maptiler.org, and follow the instructions on the web site to install.

Once you have the software installed on your Mac or PC. Follow the wizard interface. I’ve provided the settings that I’ve used below.

Chose the Google Map compatible tiles – that’s what we’re using.

Choose the file that you wish to convert.

If your imagery is geo-referenced you should see projection information in this screen. Otherwise you may have to define the geo-referencing information yourself using the ‘Georeference’ button.

The Zoom Levels are automatically calculated, however you may have to zoom the may in or out to see the imagery. You can always reduce the minimum or increase the maximum zoom to see the imagery at more scales.

PNG produces the best results, but you may want to try JPEG if space is an issue, however you may end up with black borders around the imagery.

Choose a directory where the resulting files will be created.

Select Google Maps here. Others could be chosen too. This helps when testing.

Select the defaults here.

Press Render to start creating image tiles.

Once the rendering is complete, which may take a long time depending on the size of your imagery, it is a good idea to test the results. Click on the directory hyperlink to go the tile directory.

You will see that a directory has been created with several sub-directories. Have a look at the images in the directories to see what the tiler has done.

Don’t delete tilemapresource.xml, this is the file we use in iGIS.

Click on googlemaps.html to test out whether MapTiler did it’s job. You may need to zoom in or out to see the imagery on the map.

You need to zip or compress the directory that Map Tiler created. On a Mac use Compress on a PC you can use a free zip utility, like 7 Zip.

Start iTunes with your iPhone connected, and bring up the File Sharing section under the Apps tab on your device. See Help on Import for more information. Add the zip file you created and this will automatically sync to the iPhone.

Go into Import mode on your iPhone and the imagery will appear.

Select your image and press Import.

Now edit your Project settings and choose Add Layer. Select the Imagery layer type.

Add the image that you have just created.

Go to your project, pan and zoom to your imagery in the map. Hopefully you see the imagery perfectly aligned to your other data.

Note: The project extent button will not automatically zoom to image bounds. You will have to manually pan and zoom. We’ll fix this in an update.

I hope that you’ve been able to follow this tutorial. Please contact us if you have any queries and I hope that you enjoy using iGIS with your own imagery.

Andrew

www.maptiler.org

iGIS support for MapInfo Professional Users

Whilst iGIS currently only supports the import and export of spatial data in ESRI’s shapefile format, MapInfo Professional users do not need to miss out on all the fun, as they can easily utilise their softwares built in Universal Translator tool functionality to convert MapInfo TAB datasets to and from ESRI Shapefile datasets.

Support for conversion from MapInfo TAB files to ESRI Shapefiles;

Support for conversion from ESRI Shapefiles to MapInfo TAB files;

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