Sep 27, 2013 by Zhe Guo

To every crop there is a season with optimal times for planting, sowing, and harvesting. Precisely documenting these times in a Crop Calendar through time and space, however, remains a challenge, particularly at small scales such as the pixel. But pixels are what HarvestChoice is all about.

Photo credit: IFPRI

Jun 17, 2013 by Zhe Guo

Maps describing Earth's land cover tell different stories. Which should we believe?

Aug 17, 2010 by Zhe Guo

The port shed is the total area surrounding each port for which that port has the lowest cost in terms of travel time. Travel time was estimated based on the combination of different spatial data layers, or variables, which affect the time required to travel across to the given points (i.e. cities).

Aug 17, 2010 by Zhe Guo

This surface divides sub-Saharan Africa into market sheds by measuring the nearest city or ‘market’ with a population of 20,000; 50,000; 100,000; 250,000; and 500,000 respectively. Nearness is determined by measuring the least accumulated ‘cost’ or travel time to each market center. The market shed is the total area surrounding each market for which that market has the lowest cost in terms of travel time. Travel time was estimated based on the combination of different spatial data layers, or variables, which affect the time required to travel across to the given points (i.e. cities). Market shed data can be used to determine the number of people or households that are more than likely dependent on a given market center (assuming that most people would travel to the closest market for their needs).

Aug 16, 2010 by Zhe Guo

HarvestChoice AgMarketFinder is a web-based geoprocessing GIS application that provides a quick-and-easy access to the spatially-explicit agricultural statistics databases, including crop, livestock, and rural/urban human population. No GIS skill necessary!

AgMarketFinder v2.0

Aug 15, 2010 by Zhe Guo

HarvestChoice uses ESRI ArcGIS Server as a web-based spatial data sharing/exploration platform. This post presents a quick example application using Port Sheds dataset.

ArcGIS Server App Example: Port Sheds

Aug 9, 2010 by Zhe Guo

The travel time maps indicate the degree of accessibility from a pixel to a populated place. The patterns shown here describe the geographic accessibility between places in Sub-Saharan Africa. We define accessibility as the time in hours required to travel from a given single point (1x1km pixel) to the nearest market center. Travel time to market centers is used as a proxy for market accessibility and shows the likely extent to which farming households are physically integrated with or isolated from markets.

Market

Aug 8, 2010 by Zhe Guo

Global human settlements database comprises a global dataset of about 55,000 cities and towns with populations of 1,000 or more.

City