How To Create a Digital Cemetery Map in Cemify
We often get questions from cemeteries about how they can convert their existing mapping into a digital, interactive cemetery map within our software. The answer to this question is a bit complex. This article will help introduce you to everything involved in transitioning a cemetery into a digital and online accessible GIS map in Cemify.
What is GIS?
GIS stands for "geographic information system" and describes any system for generating, viewing and analyzing data in terms of its positioning on earth's surface. A GIS system might consist of lines, shapes and/or points that are connected to more detailed information. In the context of a cemetery, a GIS system may include shapes for cemetery plots, section perimeters, roadways and more:
How is GIS data created?
One of the primary ways GIS data is created is by digitizing directly based on scanned paper mapping materials. The scanned map is first overlaid with satellite imagery so that it can be geo-referenced (aligned and positioned according to real world placement). Once geo-referenced, shapes and data are then carefully diagrammed according to the overlaid image. For example, a cemetery map might be overlaid on satellite imagery:
And then diagrammed into shapes using a GIS system:
There are a variety of GIS systems that can be used to diagram and create GIS data. One of the most generally popular GIS systems in use today is ESRI ArcGIS, but there are several other options available.
Is all GIS data the same?
No. GIS data can vary significantly depending on several factors, including:
- File Formats - certain GIS systems have their own file formats.
- Coordinate Systems - there are different coordinate zones across the globe depending on location.
- Structure Of Shape Data - the way in which shapes are created can vary and produce compatibility issues.
What structure does a GIS file have to be in to import into Cemify?
In order to import an existing GIS map into Cemify, it must be in the following format:
File Format
GeoJSON. Cemify data is imported through the use of GeoJSON. GeoJSON is an open standard format designed for representing simple geographical features. Learn more about GeoJSON.
Coordinate System
WGS 84. WGS 84 is the standard U.S. Department of Defense definition of a global reference system for geospatial information and is the reference system for the Global Positioning System (GPS). This is probably the coordinate system you are most familiar and involves a latitude and longitude pair. For example, 38.876656, -77.070347 is the center coordinate for Arlington National Cemetery.
Structure of Shape Data
Cemetery Plots (individual grave spaces) can be represented in Cemify using rectangles or complex polygons. These are typically 4+ coordinates in a series representing the perimeter of the plots. For example:
[[-121.653341, 37.119113], [-121.6533148, 37.1191227], [-121.6533197, 37.1191313], [-121.6533459, 37.1191215]]
Note: the above code is an example of GeoJSON formatted coordinates. In GeoJSON, the ordering is longitude then latitude, or easting and northing. This is contrary to the more popular formatting of latitude, longitude.
Cemetery Entities (for example, sections, blocks, lots, rows, etc.) can be represented exactly as plots are, but typically include more coordinates as they are often more complex polygons.
Cemetery Reference Objects (for example, trees, roadways, buildings, etc.) can be represented using polygons, multi-point lines and/or points.
Structure of Mapping Classifiers
Attached to the cemetery shapes should be classification which describes that shape. For example, for a plot that might be Section, Lot & Space number. To import properly into Cemify, these should be included as GeoJSON Properties. Here is an example of a GeoJSON file, including properties that describe a single plot:
{
"type": "FeatureCollection",
"name": "Hillside Cemetery",
"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
"features": [
{
"type": "Feature",
"properties": { "type" => "Plot", cemifySection": "South", "cemifyLot": "1", "cemifyPlot": "A" },
"geometry":
{ "type": "MultiPolygon",
"coordinates": [ [ [ [-121.653341, 37.119113], [-121.6533148, 37.1191227], [-121.6533197, 37.1191313], [-121.6533459, 37.1191215] ] ] ]
} }
]
}
<br>
Note that in properties, the type of shape is indicated as:
"type" => "Plot"
and the classifiers for that plot are indicated
cemifySection": "South", "cemifyLot": "1", "cemifyPlot": "A"
When adding properties to entities, it's important to include the entire chain of entities as properties. For example, you might have an entity for Section A, Block 5, Lot 7:
{
"type": "FeatureCollection",
"name": "Hillside Cemetery",
"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
"features": [
{
"type": "Feature",
"properties": { "type" => "Entity", cemifySection": "A", "cemifyBlock": "5", "cemifyLot": "7" },
"geometry":
{ "type": "MultiPolygon",
"coordinates": [ [ [ [-121.653341, 37.119113], [-121.6533148, 37.1191227], [-121.6533197, 37.1191313], [-121.6533459, 37.1191215] ] ] ]
} }
]
}
<br>
Note that the type is indicated as "Entity" and the full chain of entities is included (Section, Block & Lot):
"properties": { "type" => "Entity", cemifySection": "A", "cemifyBlock": "5", "cemifyLot": "7" }
Cemetery Reference Objects can also be included and should include a "Title" to describe the object. For example:
{
"type": "FeatureCollection",
"name": "Hillside Cemetery",
"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
"features": [
{
"type": "Feature",
"properties": { "type" => "ReferenceObject", "title": "Tool Shed"},
"geometry":
{ "type": "MultiPolygon",
"coordinates": [ [ [ [-121.653341, 37.119113], [-121.6533148, 37.1191227], [-121.6533197, 37.1191313], [-121.6533459, 37.1191215] ] ] ]
} }
]
}<br>
What options do cemeteries have for creating this data?
In order to create shape data in the appropriate format, cemeteries have a few options:
Hire Cemify
We have experience working with hundreds of cemeteries to convert their paper maps into structured GIS data in our system. While pricing varies significantly based on cemetery size and layout, on average our past projects have generally landed in the $500 - $1000 per cemetery acre range.
Do It Yourself
If you're technically savvy or have experience in the GIS field, you are welcome to create your own GIS data and import it into Cemify. Please note that the data must conform precisely with the specifications laid out above. We encourage you to share a subset of data with our support team as you get started so we can ensure its conformity to our specifications.
Hire A Third Party GIS Professional
An experienced GIS professional will be able to work with you to understand your existing mapping materials and turn them into GIS shape files. As with the DIY approach, please note that the data must confirm precisely with the specifications laid out above.
A GIS professional can cost between $65 to $250+ per hour depending on speciality and experience. Since all cemeteries are different in terms of size and layout, it can be tough to give a blanket cost estimate when hiring a third party GIS professional.
What if my cemetery doesn't have any existing survey maps?
Since most GIS systems are created using existing survey maps, it is recommended that you first generate a to-scale cemetery survey map, prior to diagramming that map in a GIS system. This often done through hiring a local survey company, who then use precision survey tools to create a to-scale map of your cemetery and plots.
Can I map a cemetery using a smartphone, such as an iPhone?
Unfortunately, iPhones and consumer smartphones are not accurate enough from a GPS perspective to enable direct field data collection / mapping. A typical smartphone will provide GPS coordinates within 30 - 60 feet. Since cemetery plots can vary by 3 feet or less, the accuracy of these devices is not sufficient.
It is possible to collect GPS points with a high precision device, extrapolate those points into 4 point plot shapes, then import into Cemify. This is an approach that might be used by a natural burial cemetery, where plot plans don't follow conventional designs.
Can you map a cemetery that has no existing maps to share, using just the satellite imagery?
While it is theoretically possible to create GIS maps using simply the shape of headstones in satellite imagery, ground truth is often obstructed by trees and shrubs. While this can work for a rough estimate of mapping, it is generally not feasible or recommended.
Do you have to use GIS mapping to use Cemify?
Absolutely not. Cemify can be used in partnership with existing paper maps (paper maps can even be scanned & imported as photos into Cemify). That said, there are certain tools (such as the interactive map and public gravesite location lookups) that are only available when using GIS mapping.
Some sort of GIS mapping system is recommended for active cemeteries, as it increases accuracy and ease of access to inventory data.