When the iGIS WiFi import page tool is used to create a *,glc file for shapefile data, each field will be described as one of the below types;
iGIS also supports a number of special field types which can be used to replace these default types. When special types are defined the application will auto populate values on feature creation/edit.
iGIS uses two sqlite databases in its backend; spatial-store.sqlite and Projects.sqlite. In most cases data can be recovered to shapefile from these files using free third party software as described in the steps below.
1. Get a copy of these backend database files off your device using third party software like; iPhone Explorer http://www.macroplant.com/iexplorer/
-Once installed, use iExplorer in its free demo mode to navigate to;
–iphone iExplorer\<*Your Device Name*>\Apps\iGIS\Documents\.database
–ipad iExplorer\<*Your Device Name*>\Apps\iGIS HD\Documents\.database
Save the spatialstore.sqlite and Projects.sqlite files to a location on your PC.
2. The spatial data in the spatial-store.sqlite database can be visualised and exported to shapefiles using the open source software Spatialite-GIS. This software can be found at the below linked site;
For a Windows 7 PC, downloaded and install; spatialite-gis-win-x86-1.0-ALPHA-1.zip
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/
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
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.
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.
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)
empty template shapefiles – 4326 WGS84
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.
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.