<?xml version="1.0" encoding="UTF-8"?>
<rfc version="3" docName="draft-kartha-grd-00" category="info" submissionType="IETF" ipr="trust200902">

  <front>
    <title abbrev="Geospatial Resource Discovery">Geospatial Resource Discovery (GRD): Problem Statement and Conceptual Architecture</title>

    <author fullname="Gokul Kartha" surname="Kartha" initials="G.">
      <organization>Independent</organization>
      <address>
        <email>kartha.gokul@gmail.com</email>
      </address>
    </author>

    <date year="2026" month="January" day="20" />

    <abstract>
      <t>The Internet provides standardized mechanisms for resolving
      identifiers, such as domain names, to network locations. These
      mechanisms assume that a client already knows the identifier of the
      resource it wishes to access. Emerging classes of applications,
      including augmented reality, autonomous systems, robotics, and
      spatial computing, operate under a different assumption. In these
      systems, discovery begins with physical presence and observer context
      rather than with a predefined name.</t>

      <t>This document describes the architectural gap addressed by a
      Geospatial Resource Discovery service. It defines the problem space,
      explains why existing standards are insufficient, and outlines a
      conceptual architecture for spatial discovery. This document is
      informational and architectural in nature. It does not define a
      protocol, data format, or implementation.</t>
    </abstract>
  </front>

  <middle>
    <section title="Introduction">
      <t>Internet architecture has historically focused on resolving semantic
      identifiers into network endpoints. Systems such as the Domain Name
      System enable scalable communication by assuming that clients already
      know the name of the resource they are attempting to reach.</t>

      <t>Emerging spatial systems invert this assumption. In augmented
      reality, autonomous navigation, and smart environments, discovery
      begins with physical location and context. A user or machine
      operating at a specific coordinate needs to ask what digital
      information is associated with the surrounding space and visible
      volume.</t>

      <t>At present, this type of discovery occurs inside closed ecosystems.
      Each platform maintains its own spatial maps, registries, and access
      mechanisms. While effective within individual systems, these
      approaches do not interoperate. This document argues that spatial
      discovery represents a missing architectural layer and describes the
      requirements for an open Geospatial Resource Discovery capability.</t>
    </section>

    <section title="Scope and Non-Goals">
      <section title="Scope">
        <t>This document focuses on the application layer. It describes a
        discovery pattern that can operate over existing transports such as
        HTTP/3 or CoAP. It intentionally avoids assumptions about rendering
        engines, device capabilities, or user interface models.</t>
      </section>

      <section title="Non-Goals">
        <t>This document does not propose changes to IP routing or DNS
        semantics. It does not define legal ownership of physical space,
        geometric rendering standards, or a global governance model for
        spatial authority.</t>
      </section>
    </section>

    <section title="Terminology">
      <t>Spatial Resource: A digital asset associated with a physical
      location or volume, such as an augmented reality annotation,
      navigation marker, or machine-readable instruction.</t>

      <t>Spatial Cell: A discrete geospatial region used for indexing and
      lookup, typically derived from a hierarchical grid system.</t>

      <t>Frustum: A three-dimensional volume defined by an observer's
      position, orientation, and field of view.</t>

      <t>Trust Anchor: An entity considered authoritative for a specific
      category of spatial information within a given context, without
      implying a single global root of trust.</t>
    </section>

    <section title="Problem Statement">
      <t>The Internet lacks a standardized mechanism to discover digital
      resources based on physical location and observer context.</t>

        <t>Existing discovery mechanisms resolve names rather than locations.
    While geographic identifiers exist (e.g., <xref target="RFC5870"/>), 
    there is no standard protocol that allows a client to query a location 
    and receive a list of available spatial resources.</t>

      <t>Spatial data is also highly application-specific. Autonomous
      vehicles, wearable devices, and smart infrastructure systems
      operating in the same physical environment cannot discover or consume
      each other's data unless they share a proprietary backend.</t>

      <t>In addition, current application protocols do not natively support
      volumetric queries. Requests such as retrieving resources within a
      three-dimensional viewing volume are not directly expressible.</t>

      <t>Finally, many spatial resources are dynamic and time-sensitive.
      Real-time spatial information, such as hazards or temporary
      instructions, requires low latency and short validity periods.
      Traditional caching assumptions are poorly suited to these
      constraints.</t>
    </section>

    <section title="Design Guidelines">
      <t>Any future specification for Geospatial Resource Discovery should
      follow a small set of architectural principles. The design should
      remain independent of transport and operate over existing Internet
      protocols. Complex geometric calculations should be performed by the
      client to preserve resolver scalability. Discovery should support
      semantic filtering so that clients can request only relevant
      categories of information. Privacy considerations must be integral to
      the design and should limit the precision of location data exposed to
      discovery services.</t>
    </section>

    <section title="Conceptual Architecture">
      <t>This section outlines a conceptual architecture referred to as
      Geospatial Resource Discovery (GRD).</t>

      <t>The physical world is divided into discrete spatial cells using a
      standard hierarchical indexing system. Representing space in this way
      allows spatial discovery to be reduced to key-based lookups rather
      than continuous geospatial computation.</t>

      <figure anchor="fig_grid" title="Hierarchical Spatial Grid">
        <artwork><![CDATA[
        +---------+---------+---------+
        | Cell A  | Cell B  | Cell C  |
        |         |         |         |
        +---------+---------+---------+
        | Cell D  | Cell E  | Cell F  |
        | (Index) | (Index) | (Index) |
        +---------+---------+---------+
        | Cell G  | Cell H  | Cell I  |
        |         |         |         |
        +---------+---------+---------+
        ]]></artwork>
      </figure>

      <t>A GRD resolver functions as a directory service. It maintains
      references to spatial resources indexed by cell identifier and
      returns pointers to the actual assets. The resolver does not host
      large content objects such as three-dimensional models.</t>

      <t>Authority over physical space is not strictly hierarchical. Multiple
      independent entities may publish resources associated with the same
      spatial cell. This introduces a fundamental architectural choice
      between client-side aggregation of multiple authorities and resolver-
      side federation of records.</t>

      <t>For example, a federated resolver simplifies client logic and can
      vouch for aggregated data integrity, but requires coordination among
      authorities. Client-side aggregation offers greater autonomy and
      avoids a central point of coordination but places the burden of trust
      evaluation and result merging on each client.</t>
    </section>

    <section title="Volumetric Query Concept">
      <t>To balance scalability and privacy, GRD follows a coarse query and
      fine filter model.</t>

      <t>The client computes its precise view frustum locally and determines
      which standard spatial cells intersect that volume. It then queries
      the resolver for resources associated with those cells, optionally
      filtered by semantic category. This translation from a continuous
      geometric volume to discrete cell identifiers allows spatial
      discovery to leverage standard, cache-friendly HTTP request
      semantics for what is inherently a spatial query.</t>

      <figure anchor="fig_frustum" title="Frustum-to-Cell Intersection">
        <artwork><![CDATA[
                / \
               /   \  <-- View Frustum
              /     \
             /       \
      +-----/---------/-----+
      | Cell X | Cell Y |   |  <-- Client requests Cell X + Y
      +--------+--------+---+      (Standard HTTP GET)
        ]]></artwork>
      </figure>

      <t>The client performs final filtering locally and discards resources
      that fall outside the exact viewing volume. This approach ensures
      that the resolver does not learn the client's precise orientation or
      gaze direction.</t>
    </section>

    <section title="Relationship to Existing Work">
      <t>Existing standards address related but distinct problems. Emergency
      location and civic addressing (e.g., GEOPRIV) focus on determining
      where a client is located rather than discovering content at that
      location. Traditional geospatial standards (e.g., OGC) emphasize
      rich data transfer and are often too heavy for low-latency, real-time
      discovery. Local service discovery mechanisms (e.g., DNS-SD) operate
      at network scope and do not scale to global spatial resolution.
      Proprietary augmented reality platforms demonstrate feasibility but
      do not provide interoperability. GRD aims to bridge these gaps at the
      architectural level.</t>
    </section>

    <section title="Security and Trust Challenges">
      <t>A primary risk in spatial discovery is reality poisoning: the
      injection of false or malicious information that directly alters a
      user's perception of the physical world. The safety implications are
      significant—consider the effect of a counterfeit right-of-way
      marker for an autonomous vehicle or a hallucinated safe path over a
      physical hazard for a first responder.</t>

      <t>GRD cannot rely on a single global root of trust. Instead, trust must
      be contextual and scoped by semantic layer and authority. A spatial
      trust chain model is required, where specific entities are recognized
      as authoritative for specific categories of information.</t>
    </section>

    <section title="Privacy Considerations">
      <t>Querying spatial cells reveals approximate location information.
      Privacy risks can be mitigated by enforcing minimum cell
      granularity, allowing clients to request additional adjacent cells to
      obscure movement patterns, and avoiding persistent state at
      resolvers. Privacy should be treated as a core architectural
      requirement.</t>
    </section>

    <section title="IANA Considerations">
      <t>This document does not request any IANA actions.</t>
    </section>

  </middle>

  <back>
    <references title="References">
     <reference anchor="RFC5870">
  <front>
    <title>A Uniform Resource Identifier for Geographic Locations ('geo' URI)</title>
    <author initials="A." surname="Mayrhofer" fullname="A. Mayrhofer">
      <organization/>
    </author>
    <author initials="C." surname="Spanring" fullname="C. Spanring">
      <organization/>
    </author>
    <date year="2010" month="June" />
  </front>
  <seriesInfo name="RFC" value="5870" />
</reference>
    </references>

    <section title="Illustrative Data Model">
      <t>This appendix is non-normative and illustrates the type of data a
      resolution service might return.</t>
      <figure>
        <artwork><![CDATA[
{
  "cell_id": "8928308280fffff",
  "resources": [
    {
      "id": "res-12345",
      "type": "safety.warning",
      "location": { "lat": 52.3, "lon": 4.9, "alt": 10 },
      "layer": "infrastructure",
      "uri": "https://city-assets.example.com/signs/stop.glb",
      "validity_ms": 60000,
      "signature": "ab382...[cryptographic proof]"
    }
  ]
}
        ]]></artwork>
      </figure>
    </section>
  </back>

</rfc>